Blackhorse .32 T-28 Trojan
09-24-2008, 11:43 AM
#26
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Join Date: Mar 2008
Location: Adelaide, Australia
Posts: 20
Blackhorse T-28 Trojan
Thanks for the feedback on the photos, I'm glad you like them. I hope to post some more soon.
There has been a bit of talk on props... I have found that 11x7 - 11x8 seems to work best on my E-flight 25 (It should be similar for your setup). I am still using the dual 2500 LiPoh and am getting over 16 mins of general flying with room to spare.
There is only one other point that I can think of and that is changing the batteries - it is a bit of a pain as you have to take the wing off. So if you can fit the bigger batteries it maybe worth your while...
I look forward to hearing from you when you are up and going.:o
Cheers,
Starks
There has been a bit of talk on props... I have found that 11x7 - 11x8 seems to work best on my E-flight 25 (It should be similar for your setup). I am still using the dual 2500 LiPoh and am getting over 16 mins of general flying with room to spare.
There is only one other point that I can think of and that is changing the batteries - it is a bit of a pain as you have to take the wing off. So if you can fit the bigger batteries it maybe worth your while...
I look forward to hearing from you when you are up and going.:o
Cheers,
Starks
09-25-2008, 10:00 AM
#28
Short Circuit Creator
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Join Date: Sep 2006
Location: Geelong, Victoria, Australia
Posts: 104
The wing removal thing is the price we pay for converting IC models to electric I guess. But is it as much a pain as wiping the exhaust residue off the side of a glow model at the end of a days flying? Not really.
The maiden flight will have to wait for the right day weather wise. As you know Starks, so far this spring in S.E Oz, it's been great weather during the week and lousy on the weekends
The maiden flight will have to wait for the right day weather wise. As you know Starks, so far this spring in S.E Oz, it's been great weather during the week and lousy on the weekends
09-30-2008, 04:46 AM
#29
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Join Date: Mar 2008
Location: Adelaide, Australia
Posts: 20
Blackhorse .32 T-28 Trojan
For those that asked about servos'... I installed JR375 in the ailerons and elevator. The slots for those will require a small amount of rework as the slots are designed to fit a standard servo - so are too big. If you need further help I can post some pictures of the wing. I have already posted a photo of the servo tray. As for the rudder I have fitted a standard servo as it has to drive the nose wheel steering as well.
Have fun,
Starks
Have fun,
Starks
09-30-2008, 12:37 PM
#30
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I used GWS "Park" HPX Servos all round. (Weight 19 grams each)
This is a high torque version of the GWS Park range (3.0 Kg torque on 4.8 volts).
They dropped right into the appropriate slots with no cutting or sanding required.
Got them from United Hobbies @ $US 12.35 each.
No problems driving the nose wheel and rudder off the one servo.
This is a high torque version of the GWS Park range (3.0 Kg torque on 4.8 volts).
They dropped right into the appropriate slots with no cutting or sanding required.
Got them from United Hobbies @ $US 12.35 each.
No problems driving the nose wheel and rudder off the one servo.
12-22-2008, 11:27 PM
#33
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Join Date: Dec 2008
Location: Plymouth UK
Posts: 26
Hello all
I am thinking about getting this lovely T-28 as my first low winger and was just wondering what you guys think about the following spec. At the moment I am looking at
XYH 3536 1100Kv 35A motor (same as tornado an turnigy motors) , 40A hobbing wing opto ESC, 4x Towerpro MG16R servos
(Dimension:29*11.2*29mm), AR6200rx and using my Evolite 2500mAh batteries of which I have 4, so doubling up is possible.
I will put the links up the motor when I can
I was wondering it those servos would fit ok ? if not I can get hold of 4 gws HPXF ones for about the same price. I have a 3A hobbywing UBEC that I was going to use in another model, that should be enough for 4 servos ?
Do you think this would make a good first low winger ?
I am thinking about getting this lovely T-28 as my first low winger and was just wondering what you guys think about the following spec. At the moment I am looking at
XYH 3536 1100Kv 35A motor (same as tornado an turnigy motors) , 40A hobbing wing opto ESC, 4x Towerpro MG16R servos
(Dimension:29*11.2*29mm), AR6200rx and using my Evolite 2500mAh batteries of which I have 4, so doubling up is possible.
I will put the links up the motor when I can
I was wondering it those servos would fit ok ? if not I can get hold of 4 gws HPXF ones for about the same price. I have a 3A hobbywing UBEC that I was going to use in another model, that should be enough for 4 servos ?
Do you think this would make a good first low winger ?
12-23-2008, 10:26 AM
#34
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Location: Geelong, Victoria, Australia
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It is not a hard plane to fly, so should be a good choice as a 1st LW model.
However , like all LW's, it does not "self correct" from a bank if you let the sticks go.
Use the GWS HPXF servo's, the extra torque will come in handy.
As for the motor- as long as it can handle a 4 cell Lipo pack. You will need at least that for the correct C of G.
Prop-- a minimum of an 11 x 7. I am using a 12 x 6 but intend to try an 11 x 7, 3 bladed prop. Oh, and I don't use "E" props on models of this size. Personally, I feel that modern brushless outrunners are strong enough to swing i.c props.
Good luck.
However , like all LW's, it does not "self correct" from a bank if you let the sticks go.
Use the GWS HPXF servo's, the extra torque will come in handy.
As for the motor- as long as it can handle a 4 cell Lipo pack. You will need at least that for the correct C of G.
Prop-- a minimum of an 11 x 7. I am using a 12 x 6 but intend to try an 11 x 7, 3 bladed prop. Oh, and I don't use "E" props on models of this size. Personally, I feel that modern brushless outrunners are strong enough to swing i.c props.
Good luck.
12-23-2008, 12:05 PM
#36
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The "Box" specs are for an AXI 2820 series motor spinning an 11 x 6 prop. The factory do not tell you how they achieved the C of G.
A 3 cell Lipo will most likely leave you tail heavy and you will need to add ballast.
My pack is a 4S1P 4400Ma/H, weighs 420 grams and gives me around 15 mintues of flight.
The model is slightly nose down at the C of G point with this pack.
You don't say whether your packs are 2 or 3 cell.
If 2 cell, then 2 in Series will be fine, (to make a 4S1P pack) but flight duration will be short. 2500Ma/H is very small for a model this size.
If 3 cell, you will have to add ballast (deadweight) to get the C of G and will not get the "grunt" of the extra cell.
As regards the servo's/ESC. I don't trust BEC setups in large models. Seen too many go wrong with disasterous results. An ESC bypass is very easy to set up (all you need is a 6 inch servo extension between the ESC and the Rx and cut the RED wire.)
I use a 4 cell AAA Sanyo "Eneloop" pack (weighs very little) to power the Rx and servo's. (Safer as far as I am concerned.)
However, you use what you want.
A building tip. Blackhorse supply self tapping wood screws to hold the nose gear in place. Over time these screws will tear out of the firewall. Substitute blind nuts and bolts in their place.
A 3 cell Lipo will most likely leave you tail heavy and you will need to add ballast.
My pack is a 4S1P 4400Ma/H, weighs 420 grams and gives me around 15 mintues of flight.
The model is slightly nose down at the C of G point with this pack.
You don't say whether your packs are 2 or 3 cell.
If 2 cell, then 2 in Series will be fine, (to make a 4S1P pack) but flight duration will be short. 2500Ma/H is very small for a model this size.
If 3 cell, you will have to add ballast (deadweight) to get the C of G and will not get the "grunt" of the extra cell.
As regards the servo's/ESC. I don't trust BEC setups in large models. Seen too many go wrong with disasterous results. An ESC bypass is very easy to set up (all you need is a 6 inch servo extension between the ESC and the Rx and cut the RED wire.)
I use a 4 cell AAA Sanyo "Eneloop" pack (weighs very little) to power the Rx and servo's. (Safer as far as I am concerned.)
However, you use what you want.
A building tip. Blackhorse supply self tapping wood screws to hold the nose gear in place. Over time these screws will tear out of the firewall. Substitute blind nuts and bolts in their place.
12-23-2008, 12:29 PM
#37
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Join Date: Dec 2008
Location: Plymouth UK
Posts: 26
They are 3 cell, which poors cold water over the T-28 for me as that adds £120 to the build for 2 4cell lipos. The only thing I could do is build it up for 4cell and run it on 3 until I can afford the batteries. There is a elapor Parkzone T-28 wich is just a little smaller.
12-23-2008, 04:23 PM
#38
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Join Date: Aug 2005
Location: Simi Valley,CA
Posts: 1,166
My BH Models T-28 is powered by an E-Flite Power 25 and I use a 3S4200mAh LiPo pack and I am able to balance the model by moving the battery pack forward a bit. I don't think you absolutely need a 4 cell pack.
12-23-2008, 08:07 PM
#39
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Have a look for a Turnigy equivalent to the AXI 2820 series. TR35-48B or 48C, or one of the TR42 series. These are plenty cheap (around 18 UK pounds from UH) and are in the ideal KV range to power this model. (between 700-900Kv)
They should enable flying it on 3 cells.
2 of your 3 cell packs hooked up in PARALLEL, will give you 5000Ma/H (Oodles of flying time) and plenty of useful weight to play with for the C of G. (UH sell the appropriate connector leads to do this.)
Alternatively, look at the United Hobbies "Zippy" lipos. That is all I use these days as do many of the electric flyers at the local R/C Flying Club and they are just as good as the big $$$ brands.
A 15C 4 cell 4000 Ma/H "Zippy" pack cell is 46 UK Pounds (on current exchange rates) Buy 1 at a time as you can afford!
(My T-28 packs are only 20 C.)
This pack will give you more than sufficient current, (60 amps max) plenty for a motor only pulling around 35-38 amps.
The BH T-28 is a far better choice than the Parkzone foamy version.
They should enable flying it on 3 cells.
2 of your 3 cell packs hooked up in PARALLEL, will give you 5000Ma/H (Oodles of flying time) and plenty of useful weight to play with for the C of G. (UH sell the appropriate connector leads to do this.)
Alternatively, look at the United Hobbies "Zippy" lipos. That is all I use these days as do many of the electric flyers at the local R/C Flying Club and they are just as good as the big $$$ brands.
A 15C 4 cell 4000 Ma/H "Zippy" pack cell is 46 UK Pounds (on current exchange rates) Buy 1 at a time as you can afford!
(My T-28 packs are only 20 C.)
This pack will give you more than sufficient current, (60 amps max) plenty for a motor only pulling around 35-38 amps.
The BH T-28 is a far better choice than the Parkzone foamy version.
12-23-2008, 11:15 PM
#40
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Join Date: Dec 2008
Location: Plymouth UK
Posts: 26
Now I can post links, those turnigy motors look an awfull lot like these ones.
35-48 http://www.brchobbies.co.uk/?page=sh...ditem&item=965
My orginal choice was this one http://www.brchobbies.co.uk/?page=sh...ditem&item=961
Or this one http://www.brchobbies.co.uk/?page=sh...ditem&item=963
The 3536 seems to be the most powerful one on 3cells with out the prop data for the 3542 and 3548 it's difficult to work out what power I would get out of them on 3cell. In fact I find the whole thing very confusing, those motors go under several different brands, turnigy, purple power, wasp, tornado and xhy and they all seem to have different prop recomendations and its a tad bewildering. I can see why people pay the axi prices at least they know what they are getting lol
35-48 http://www.brchobbies.co.uk/?page=sh...ditem&item=965
My orginal choice was this one http://www.brchobbies.co.uk/?page=sh...ditem&item=961
Or this one http://www.brchobbies.co.uk/?page=sh...ditem&item=963
The 3536 seems to be the most powerful one on 3cells with out the prop data for the 3542 and 3548 it's difficult to work out what power I would get out of them on 3cell. In fact I find the whole thing very confusing, those motors go under several different brands, turnigy, purple power, wasp, tornado and xhy and they all seem to have different prop recomendations and its a tad bewildering. I can see why people pay the axi prices at least they know what they are getting lol
12-23-2008, 11:28 PM
#41
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Join Date: Dec 2008
Location: Plymouth UK
Posts: 26
As for batteries I cant find the zippy ones in the uk shops (thought I had seen them) these get some good right ups though http://www.giantcod.co.uk/loong-3000...4a3be3a17ad347
And this one http://www.giantcod.co.uk/loong-3000...4a3be3a17ad347
All this still adds up though, I am looking at a seagull pc9 which is a cheaper build but does not have the character of the T-28 lol
And this one http://www.giantcod.co.uk/loong-3000...4a3be3a17ad347
All this still adds up though, I am looking at a seagull pc9 which is a cheaper build but does not have the character of the T-28 lol
12-24-2008, 06:51 AM
#42
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Join Date: Sep 2006
Location: Geelong, Victoria, Australia
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Buy the Zippy packs direct from United Hobbies. They are what makes Eleccy flying affordable. If I was having to buy packs etc down here, I would have stuck to glow powered models.
And as for the Turnigy stuff etc-- well, yes, welcome to the world of Asian Electric Flight. Don't know if you have ever seen the film "Empire of the Sun" with a young Christian Bale in it. But there is a scene just after a spectacular attack on a Japanese Airfield by some P51's, where the character played by Bale is told "Try not to think too much!" Best take the same advice.
Select your brand and go with the specs recommended by that brand manufacturer. Don't compare them with what may of may not be another brand that looks the same, even though that may be the case. The name difference is probably the reason why the specs are different anyway.
You will find that Turnigy ECS's are also sold as Hobbywing, Hextronic and a myriad of other names.
Turnigy motors are quite o.k. And if they do "die"--are very cheap to replace. That's the beauty of them. They allow us limited budget flyers to go fly.
If you want to spend megabucks on something that will still be going strong in 15 years, then look at the MVVS range of electric motors. It's sorta like the difference between buying a Daewoo and a Rolls Royce. They both do the same thing, but one will last a lot longer than the other.
This model fly's well with motors in the 700-900 Kv range, props between 11x6 - 12 x 7 (depending on the ground clearance)and 3 or 4 cell lipo packs depending upon motor choice. ESC--- 40 - 60 amps, once again, depending on the motor, number of cells and prop size. Invest in something like a "Watts Up" meter, it helps make the prop selection a lot easier. (Just prop it with as big a prop as you can that does not exceed the motors max specs at full rpm.) See:
http://www.hobbycity.com/hobbycity/s...Power_Analyzer
Looking at the links you posted-- the WASP 35-48 is the better choice for this model, from the 3 alternatives you considered.
And if you really have your heart set on this model-- then go ahead and get it.
O.K., it may mean a couple of months longer wait to get everything else you will need to fly it together, but it will be worth it.
Good luck.
And as for the Turnigy stuff etc-- well, yes, welcome to the world of Asian Electric Flight. Don't know if you have ever seen the film "Empire of the Sun" with a young Christian Bale in it. But there is a scene just after a spectacular attack on a Japanese Airfield by some P51's, where the character played by Bale is told "Try not to think too much!" Best take the same advice.
Select your brand and go with the specs recommended by that brand manufacturer. Don't compare them with what may of may not be another brand that looks the same, even though that may be the case. The name difference is probably the reason why the specs are different anyway.
You will find that Turnigy ECS's are also sold as Hobbywing, Hextronic and a myriad of other names.
Turnigy motors are quite o.k. And if they do "die"--are very cheap to replace. That's the beauty of them. They allow us limited budget flyers to go fly.
If you want to spend megabucks on something that will still be going strong in 15 years, then look at the MVVS range of electric motors. It's sorta like the difference between buying a Daewoo and a Rolls Royce. They both do the same thing, but one will last a lot longer than the other.
This model fly's well with motors in the 700-900 Kv range, props between 11x6 - 12 x 7 (depending on the ground clearance)and 3 or 4 cell lipo packs depending upon motor choice. ESC--- 40 - 60 amps, once again, depending on the motor, number of cells and prop size. Invest in something like a "Watts Up" meter, it helps make the prop selection a lot easier. (Just prop it with as big a prop as you can that does not exceed the motors max specs at full rpm.) See:
http://www.hobbycity.com/hobbycity/s...Power_Analyzer
Looking at the links you posted-- the WASP 35-48 is the better choice for this model, from the 3 alternatives you considered.
And if you really have your heart set on this model-- then go ahead and get it.
O.K., it may mean a couple of months longer wait to get everything else you will need to fly it together, but it will be worth it.
Good luck.
Last edited by Bellakelpie; 12-24-2008 at 07:09 AM.
12-24-2008, 11:11 AM
#43
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Join Date: Dec 2008
Location: Plymouth UK
Posts: 26
Thanks for that. I may just get the airframe and then go from there lol. I think my next purchase will be a "watts up" metre or one of these http://www.rc-log.co.uk/index.php?ta...&product_id=45
I will then get the power train, that 3548 will do 650W on 5cell so I suppose that's plenty of scope for more power, and dragging 2x3cell packs around the sky until I can afford some 4 cell ones. Of the "hobbywing esc" 40A or 60A on 4cell ? looking at the specs the 40A one seem ok but that's on paper lol
Once again thanks for the help, will now ruminate one this over xmas
I will then get the power train, that 3548 will do 650W on 5cell so I suppose that's plenty of scope for more power, and dragging 2x3cell packs around the sky until I can afford some 4 cell ones. Of the "hobbywing esc" 40A or 60A on 4cell ? looking at the specs the 40A one seem ok but that's on paper lol
Once again thanks for the help, will now ruminate one this over xmas
12-25-2008, 04:26 AM
#44
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Join Date: Sep 2006
Location: Geelong, Victoria, Australia
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Might as well go with the 60 Watt ESC. Then you have some buffering capacity if and when you decide to go up 1 or 2 cells.
As long as you prop it so that at max rpm, the motor's current draw is at the upper end (but still within) the manufacturer's max efficiency specs, everything will be o.k.
That's the beauty of a Watt meter. You can try a variety of props until you find the one that gives you the best results and then go fly with that.
I have found that the English "RAM" I.C. props give the best results. Better thrust, lower noise and less current draw, than the APC "E" props. Also in practical flying comparisions, they make the model more alive.
I have the "little" T-28's big brother also waiting to be built (I love Radials) but the current economic conditions have stymied me for a while. Same with plans to get an 'E-Flight' DHC2 Beaver. The price of the latest batch of these kits to arrive just jumped $Aust 120.
Ouch!
As long as you prop it so that at max rpm, the motor's current draw is at the upper end (but still within) the manufacturer's max efficiency specs, everything will be o.k.
That's the beauty of a Watt meter. You can try a variety of props until you find the one that gives you the best results and then go fly with that.
I have found that the English "RAM" I.C. props give the best results. Better thrust, lower noise and less current draw, than the APC "E" props. Also in practical flying comparisions, they make the model more alive.
I have the "little" T-28's big brother also waiting to be built (I love Radials) but the current economic conditions have stymied me for a while. Same with plans to get an 'E-Flight' DHC2 Beaver. The price of the latest batch of these kits to arrive just jumped $Aust 120.
Ouch!
12-25-2008, 01:44 PM
#45
Member
Join Date: Dec 2008
Location: Plymouth UK
Posts: 26
Merry Christmas ! I have enough for the kit and either power train or rx (ar6200) so with a bit of saving...
Ok, I will be able to get these batteries in January http://www.giantcod.co.uk/loong-4300...4a3be3a17ad347
They have been mentioned in a positive light in the magazines.
The 3548 and 60A opto esc are £54 or £45 from the budget supplier above (assuming they are the same motor) so with that in mind do you think the following combo would be enough http://www.brchobbies.co.uk/?page=sh...ditem&item=338
Specs of the above motor http://www.himodel.com/electric/HiMo...BL2820_07.html
I know I am thinking to much lol just want the best value of money
Ok, I will be able to get these batteries in January http://www.giantcod.co.uk/loong-4300...4a3be3a17ad347
They have been mentioned in a positive light in the magazines.
The 3548 and 60A opto esc are £54 or £45 from the budget supplier above (assuming they are the same motor) so with that in mind do you think the following combo would be enough http://www.brchobbies.co.uk/?page=sh...ditem&item=338
Specs of the above motor http://www.himodel.com/electric/HiMo...BL2820_07.html
I know I am thinking to much lol just want the best value of money
Last edited by MThemadhatter; 12-25-2008 at 03:32 PM.
12-25-2008, 09:21 PM
#46
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Join Date: Sep 2006
Location: Geelong, Victoria, Australia
Posts: 104
You are on the right track now. That combo should be more than sufficient to power the model. And the price looks good.
Get yourself a Watt Meter as well and test the combo out on a RAM 11 x 6 and 11 x 7 IC prop.
(Don't forget to balance them 1st though)
You may find that you don't need the 4 cell Lipo.
The Loong Max Lipos are another case of "same items under a different name" originating in Asia.
They are now sold as "ZIPPY" in China.
And they are good batteries. (I have 6 LM packs)
If you do buy Loong Max, make sure though that you have an appropriate JST Plug balance charger lead so that you can charge the pack up.
To explain: (Just in case, but you probably already know)----Modern lipo chargers come with either an inbuilt balancer or you use something like an LBA10 balancer, connected between the charger and the pack. You will need either a "JST" balance plug lead or a "Polyquest" balance plug lead, to connect the balancer to the battery, depending upon the type of plug used by the pack manufacturer.
In the case of Loong Max packs- a JST plug lead.
These leads are cheap- under $US2 usually and any good HS dealing in Electric Flight will have them.
Another build tip. The cowl opening on the T-28 is too big to allow proper cooling. The rule is "1 (cold air in) to 3 (warm air out)" - in other words, for every square inch of cowl opening for cold air ingress, you must have 3 square inches of outlet sowewhere downstream , either at the rear of the cowl or holes in the fuselage, or both, for warm air exhaust. The opening on the T-28 is massive-- too big really.
I blanked off a good portion of the outer part of the cowl with 2mm thin plastic card CA'd to the inside of the cowl, (and painted black to disguise it) allowing air to enter an inner circle only, basically so that it just flowed around the motor. On the bottom part of the cowl I left it unblanked right to the outler edge of the cowl, in line with some holes drilled in the firewall, to allow air to flow around the battery/ESC.
NB--My ESC is inside the fuselage, in front of the battery, but only because of the way my motor is designed.
On the motor you are looking at, there would be room to attach the ESC to the front side of the firewall, using cable ties through small holes drilled in the firewall for attachment purposes. Then just make sure that there is cooling air flow inlet in line with the ESC.
But I think in this case, with such a low current draw to what the ESC is designed for, cooling will not really be an issue.
As for the warm air outlet. The hole in the firewall where the I.C engine fuel tank would normally poke through, is covered by the factory supplied engine mount. So you will have to drill other bigger ones of around 8 - 9 mm diameter, around the motor. That will allow air to escape into the fuselage. A couple of slots cut into the underside of the fuselage behind the wing, will take care of the outlet.
And you will have to cut a slot on the underside of the cowl to allow the nosewheel leg to pass through. That will also be part of the warm air outlet flow.
And that factory supplied engine mount.
If you use it, reinforce all the corners with triangular balsa stock and then cover the whole assembly with light duty fibreglass cloth/24 hour finishing epoxy coat before you mount it to the model. (From my "Lessons learnt about BH kits " book)
Other wise use an appropriate length, after market, metal mount.
Looking at the instructions in my kit, I would look at using something like
http://www.hobbycity.com/hobbycity/s...-30_size_motor
or
http://www.hobbycity.com/hobbycity/s...nts_(4pc)_20mm
mounted to the supplied motor mount back plate included in the kit.
Lastly the supplied wheels in the kit-- Square! (just like the ones British Rail used to use on the rolling stock on the Charing Cross - Hastings line many years ago) -- Chuck 'em away and use some good "Dubro" lightweight replacements.
Anyway, you have hours of "fun" and a few "explosive expletive" moments to look forward to. You will find it all worth it though and will learn a lot more about this great hobby. Any further build issues, leave a message on this thread. There are plenty of guys out there who have built this model up.
Get yourself a Watt Meter as well and test the combo out on a RAM 11 x 6 and 11 x 7 IC prop.
(Don't forget to balance them 1st though)
You may find that you don't need the 4 cell Lipo.
The Loong Max Lipos are another case of "same items under a different name" originating in Asia.
They are now sold as "ZIPPY" in China.
And they are good batteries. (I have 6 LM packs)
If you do buy Loong Max, make sure though that you have an appropriate JST Plug balance charger lead so that you can charge the pack up.
To explain: (Just in case, but you probably already know)----Modern lipo chargers come with either an inbuilt balancer or you use something like an LBA10 balancer, connected between the charger and the pack. You will need either a "JST" balance plug lead or a "Polyquest" balance plug lead, to connect the balancer to the battery, depending upon the type of plug used by the pack manufacturer.
In the case of Loong Max packs- a JST plug lead.
These leads are cheap- under $US2 usually and any good HS dealing in Electric Flight will have them.
Another build tip. The cowl opening on the T-28 is too big to allow proper cooling. The rule is "1 (cold air in) to 3 (warm air out)" - in other words, for every square inch of cowl opening for cold air ingress, you must have 3 square inches of outlet sowewhere downstream , either at the rear of the cowl or holes in the fuselage, or both, for warm air exhaust. The opening on the T-28 is massive-- too big really.
I blanked off a good portion of the outer part of the cowl with 2mm thin plastic card CA'd to the inside of the cowl, (and painted black to disguise it) allowing air to enter an inner circle only, basically so that it just flowed around the motor. On the bottom part of the cowl I left it unblanked right to the outler edge of the cowl, in line with some holes drilled in the firewall, to allow air to flow around the battery/ESC.
NB--My ESC is inside the fuselage, in front of the battery, but only because of the way my motor is designed.
On the motor you are looking at, there would be room to attach the ESC to the front side of the firewall, using cable ties through small holes drilled in the firewall for attachment purposes. Then just make sure that there is cooling air flow inlet in line with the ESC.
But I think in this case, with such a low current draw to what the ESC is designed for, cooling will not really be an issue.
As for the warm air outlet. The hole in the firewall where the I.C engine fuel tank would normally poke through, is covered by the factory supplied engine mount. So you will have to drill other bigger ones of around 8 - 9 mm diameter, around the motor. That will allow air to escape into the fuselage. A couple of slots cut into the underside of the fuselage behind the wing, will take care of the outlet.
And you will have to cut a slot on the underside of the cowl to allow the nosewheel leg to pass through. That will also be part of the warm air outlet flow.
And that factory supplied engine mount.
If you use it, reinforce all the corners with triangular balsa stock and then cover the whole assembly with light duty fibreglass cloth/24 hour finishing epoxy coat before you mount it to the model. (From my "Lessons learnt about BH kits " book)
Other wise use an appropriate length, after market, metal mount.
Looking at the instructions in my kit, I would look at using something like
http://www.hobbycity.com/hobbycity/s...-30_size_motor
or
http://www.hobbycity.com/hobbycity/s...nts_(4pc)_20mm
mounted to the supplied motor mount back plate included in the kit.
Lastly the supplied wheels in the kit-- Square! (just like the ones British Rail used to use on the rolling stock on the Charing Cross - Hastings line many years ago) -- Chuck 'em away and use some good "Dubro" lightweight replacements.
Anyway, you have hours of "fun" and a few "explosive expletive" moments to look forward to. You will find it all worth it though and will learn a lot more about this great hobby. Any further build issues, leave a message on this thread. There are plenty of guys out there who have built this model up.
12-31-2008, 06:26 PM
#47
Member
Join Date: Dec 2008
Location: Plymouth UK
Posts: 26
Thank's for all the advice, I am looking at some alternatives to the stock motor mount. Now I believe that this https://shop.graupner.de/webuerp/ser...WAESselect=GBP is the same model but with Graupner on the box ? if so I can buy spare bits straight from them ! http://217.119.48.234/webuerp/AA?suc...WAESselect=GBP
There is a review here, http://www.rcgroups.com/forums/showt...ghlight=trojan I am sure they are the same ?
There is a review here, http://www.rcgroups.com/forums/showt...ghlight=trojan I am sure they are the same ?
12-31-2008, 08:53 PM
#48
Short Circuit Creator
Thread Starter
Join Date: Sep 2006
Location: Geelong, Victoria, Australia
Posts: 104
It's the same kit.
Graupner also do the same deal with "Phoenix" models. But since the 2 company's (BH and Phoenix) are owned by 2 brothers in Vietnam, (who are very active R/C flyers) and share the same suppliers for many of their kit "bits", it's not suprising that they also co-operate on marketing.
There is nothing wrong with the stock mount design, it just needs some very easy and simple reinforcing. The one thing you will find about Asian made ARF kits is that there is always something that needs changing or extra work done. Be it the stuff in the box such as hinges or wheels, or lack of decent or enough glue around critical joints.
The BH and Phoenix kits are usually pretty good glue wise, but the wheels and hinges supplied in the kits do leave something to be desired.
The engine mount on the T-28 is o.k, but the wood used to make it is balsa sheeted ply which is it's weakness. You can use the kit mount if it is reinforced, or you can cut yourself a new one from decent marine grade 3 ply, using the supplied mount as a template.
I also have a Phoenix "Rainbow" high winger. The timber mount in that is identical. When I 1st flew it I soon realised that the mount was not up to scratch supporting a motor of Speed 500 size. (it cracked.)
The problem, as I said, was the grade of wood used, so I set about bringing it up to scratch.
The main problem was the front plate (which failed) and so a new one was made from decent 3 ply.
I cut out 2 identical plates, using the supplied plates as a template. However I ensured that the wood grain in each was at 90 degrees to the other (cross grain) for added strength and then epoxied them together.
I used the kit side pieces and braced each corner with a piece of triangular balsa stock epoxied in place and to finish things off and then just cut out some very light fibreglass cloth pieces to fit over the assembled mount and glued them on with 24 hour finishing epoxy. Possible overkill, but who knows. Better overkill than "... "sh*@! why didn't I do that when I built the model...."
Oh, and before the cloth was applied, I drilled holes in the face in line with the air cooling holes on the motor. (for cooling air to enter the motor naturally) Remember to cut away the cloth (after the resin has dried) with a modelling knife where there are air cooling gaps.
Not hard at all. And the mount on the Rainbow has not given me any grief at all.
That is all you would have to do if using a traditional design motor that has the power supply leads coming from the side.
On my T-28, I used a different design motor which did not have these leads, so did not have to use the mount as such, only the base plate.
Graupner also do the same deal with "Phoenix" models. But since the 2 company's (BH and Phoenix) are owned by 2 brothers in Vietnam, (who are very active R/C flyers) and share the same suppliers for many of their kit "bits", it's not suprising that they also co-operate on marketing.
There is nothing wrong with the stock mount design, it just needs some very easy and simple reinforcing. The one thing you will find about Asian made ARF kits is that there is always something that needs changing or extra work done. Be it the stuff in the box such as hinges or wheels, or lack of decent or enough glue around critical joints.
The BH and Phoenix kits are usually pretty good glue wise, but the wheels and hinges supplied in the kits do leave something to be desired.
The engine mount on the T-28 is o.k, but the wood used to make it is balsa sheeted ply which is it's weakness. You can use the kit mount if it is reinforced, or you can cut yourself a new one from decent marine grade 3 ply, using the supplied mount as a template.
I also have a Phoenix "Rainbow" high winger. The timber mount in that is identical. When I 1st flew it I soon realised that the mount was not up to scratch supporting a motor of Speed 500 size. (it cracked.)
The problem, as I said, was the grade of wood used, so I set about bringing it up to scratch.
The main problem was the front plate (which failed) and so a new one was made from decent 3 ply.
I cut out 2 identical plates, using the supplied plates as a template. However I ensured that the wood grain in each was at 90 degrees to the other (cross grain) for added strength and then epoxied them together.
I used the kit side pieces and braced each corner with a piece of triangular balsa stock epoxied in place and to finish things off and then just cut out some very light fibreglass cloth pieces to fit over the assembled mount and glued them on with 24 hour finishing epoxy. Possible overkill, but who knows. Better overkill than "... "sh*@! why didn't I do that when I built the model...."
Oh, and before the cloth was applied, I drilled holes in the face in line with the air cooling holes on the motor. (for cooling air to enter the motor naturally) Remember to cut away the cloth (after the resin has dried) with a modelling knife where there are air cooling gaps.
Not hard at all. And the mount on the Rainbow has not given me any grief at all.
That is all you would have to do if using a traditional design motor that has the power supply leads coming from the side.
On my T-28, I used a different design motor which did not have these leads, so did not have to use the mount as such, only the base plate.
