Bellakelpie

Going to convert a BH .32 size T-28.

I have ordered one of the new MVVS 4.6/840 Inrunner/outrunners (their words, not mine) from well know RC Universe contributor and MVVS "techspert", Dar Zeelon, to power it..

More soon as the component parts arrive and building commences.

Starks

I have posted a few photos of my T-28 .32 in the Gallery. I'm interested to know how you go with the MVVS option...

Bellakelpie

Hi Starks,
I am just waiting on the servo's I ordered, (GWS Park "F") so I can commence construction.
The MVVS is too long to utilise the supplied electric motor box. But by mounting the motor to the rear plate of the aforementioned motor box and then in turn mounting the plate to the firewall, it is a perfect fit lengthwise .

Starks

One thing I did notice when putting the fin in was the clearance or lack there of, between the base of the fin and the top of the horizontal stab in front of the elevator. Mine had a slight gap under the leading edge of the fin and the fuselage where it fits. Worth a check,

Starks

simibill

I never heard of this MVVS motor, can you give me some details?

Thanks,

Starks

Never used the MVVS motor myself, I'm interested to see the comparison between it and the E-flight 25 I'm using. I installed the E-Flight 25 as it was an easy conversion for the Trojan and fits the supplied mount. I have also used dual 2500Mah Lipo's which has the added bonus of gaining a good C of G.

Starks

I test flew the T-28 yesterday with pretty good results. Very gentle, no bad vices - generally very pleased. The E-Flight 25 gave very realistic performance with a 5min flight using 450Mah on both batteries. The only issue being the supplied engine mount coming loose inflight due to torque ending an otherwise nice first flight (slight damage to cowl).

control throws were as per the instructions but I dropped the rates to 65% on ailerons and 60% on the elevator which were fine for the first flight. @ 3deg nose up with 1/4 throttle gave almost hands off approach and landing... Photos still to come...

simibill

I didn't know there was a .32 size T-28. I only know of the .60 size 7 pound version. Can you tell me where you got this model?

Thanks,

Starks

The .32 size T-28 is very similar to the .60 size version and comes with the option of glow or electric and all hardware for either version is included in the kit and the wing is two piece - gotta love that...

Specs are: wingspan - 125cm (49.21"), length -104cm (40.94"), weight - 1.75kg (3.85Lbs). The suggested motor is the AXI 2826/10, I'm using an E-Flight 25 (individual choice).

Since I live in Adelaide Australia I'm not sure who would distribute them in your area, I got mine from a local hobby store in Adeleide.

simibill

Thanks for the info. The .32 version is not available in the states. Too bad as I think this would be the perfect size. Converting the .60 version to electric is too costly for me. Adelaide where the clocks are off by one half hour. Nice town, I was there back in the 70's.

Bellakelpie

Been some time since I visited this thread.

Simibill, you ask re the MVVS electrics. MVVS have gotten right out of small 2 strokes and are replacing their range with various size Brushless Outrunners.

If you check out http://www.puffinmodels.com/category.php?dept=176
all the info about these fine motors can be read there.

The model went together without any real dramas, I did have problems with the main gear undercarriage wire though. The slots in the wings for the wire were a size too wide, allowing the wire to move around in the wing slots, so I had to sleeve the wire with heat shrink to allow a snug fit.

As usual with ARF's, the supplied wheels were of the square variety and also too small for the grass fields I fly off, so larger, lightweight wheels were substituted.

The length of the MVVS motor meant that I only had to use the ply back plate of the supplied motor mount. I mounted this to the firewall via 3 blindnuts and bolts and then attached the motor to the plate with 4 more.

Blackhorse only supplied CA hinges, cut in half, for the control surfaces. Now really, 1/2 a hinge is going to save 2/5ths of stuff all in weight, so I substituted full size Great Planes CA hinges.

I am still waiting for a 4 cell lipo to arrive from United Hobbies in Hong Kong, so no maiden flight yet. I suspect that the factory (in China) is shut for the Olympic games, so do not expect the pack to arrive before September.

I am using a Hobbywing 40 amp ESC with BEC disabled. A light weight 4 cell AAA Sanyo "Eneloop" pack supplies the power to the Rx and servo's.

Once the Lipo arrives, I can do some prop testing to decide the flight prop.
Its a choice between an Aero Naut 10.5 x 8 "E" prop, a R.A.M. 12 x 6 or a M.A. 3 bladed 11 x 7.

Starks

Nicely built,

I did use the supplied hinges on mine but did pin them as well. The wheels have not been an issue as yet but I can understand they could be a problem in long grass.
I have also mucked about with a few prop sizes and found that an 11 x 7 two bladed wooden (XOAR) has worked the best so far. It is light well balanced and gives the plane a bit extra poke without any noticeable extra current draw from the previous 10 x 5 APC. But as with all wooden props it is unforgiving.
The 4 cell pack was offered to me as an option as well but at the time I only had a three cell charger (since updated). But I did find that the dual 2500 packs have given me a perfect C of G when placed about 10mm from the battery locating screw. But I do think the 4 cell pack would offer better performance.
I have also had a photographer friend of mine take some photos of mine flying in outback South Australia which I hope to have posted in the next couple of weeks.

Cheers,

Starks

Bellakelpie

Hi Starks,
What motor are you using? Blackhorse recommend an AXI 2826/10 and a 3 cell 3500 Ma/H Lipo.
MVVS recommend a 4 cell Lipo for the motor/model combo in my case.
The prop size would differ according to the Kv rating and size of the motor used.
Personally I am not a big fan of APC "E" props on bigger electric models. I find them too noisy and prefer to use Bolly or R.A.M. IC props. I find that I get better performance. less noise and lower current draw.
I am still waiting on the 4 cell Lipo so I can start testing/flying.

I also have the 64 inch "big brother" T-28 waiting in the wings for 4 stroke installation or possible EP conversion. It has been done successfully elsewhere.

I was going through that kit a few days ago and noticed that like the little T-28 featured on this thread, Blackhorse have not included a complete set of decals to finish off the model.
So I have had a local decal maker make me a new set of vinyl "NAVY" insignia and ordered a sheet of "Major Decals" US "Stars and Bars" insignia to suit.

So anyone from "Blackhorse" who may happen to read this thread, PLEASE, ensure that their are sufficient decals in the box to finish the model off. Having only one "NAVY" decal for only one side of the model and also for one wing, is frustratingly stupid..

One comment about the electric motor mount. I learnt from my Phoenix "Rainbow", that if you are going to use the supplied Electric Motor mounts in Seagull, Phoenix or Blackhorse electric or IC/Electric combo ARF models, always reinforce the corners and then completely fibreglass the mount before you mount the motor. The designs and timber used by all 3 company's are very similar and have the same weaknesses.

Starks

Yep the big question what motor??? I kept it simple and went with the E-Flight 25 (E-Flight have seen the light and labelled their motors as a direct equivalent to the two stroke so it was an easy choice) with a DualSky 40A speedy. So I'm not sure what the conversion between yours and mine but it has ample power. Like you I have gone off the APC props but in my case I have switched to an 11 x 7 wooden prop - I think the brand is XOAR and it has made quite a difference. If you do go that way you may need to check the depth of the prop as they come in two sizes but are not identified as such. I’m glad to see that your motor didn’t need the supplied mount (good move) as the wooden one in the kit twisted with engine torque and took some bark off my cowl (BlackHorse if you’re reading please fix with the next batch). In the end I cut it down and turned the motor around.

As for the batteries I have heard people using 3 and 4 cell battery combinations. I'm using dual 2500 packs (what I had at the time) so a single 3500 should be ample.

The EP conversion on the .60 T28 sounds great. I would be interested in seeing the outcome as I’m quite pleased with .32 and think the EP .60 sounds like a good next project :-)

Hope I was some help, keep me posted.

Cheers,

Starks

Bellakelpie

Hi Starks,

Thanks for the info.

My motor is the equivalent of a .32 c.i 2 stroke.

MVVS use CC equivalents in the I.D. of their motors. Mine is a 4.6/860 which translates to a 4.6 cc 2 stroke equivalent and 860 Kv. It ahs an integral cooling fan which draws air through the rear of the motor and exits it on the sides at the front.
MVVS make them right up to 1.20 C.I. size.

What is not shown in the pic I attached is the series of 9mm holes I drilled in the firewall around the engine to allow air to flow around the motor and exit into the fuselage. I then cut rectangular pieces out of the fuselage sides. These slots are concealed by the raised molded cowl flaps. I figure that air passing over these raised sections will create a vacumn, sucking (warm) air out of the slots. That's the theory anyway-- flight testing will see if it works.

There is a good review (with links to flight video) of an electric conversion of the big BH T-28 over on RC Groups at
http://www.rcgroups.com/forums/showthread.php?t=731144
Looks a relatively uncomplicated conversion.

Starks

I totally agree, always a good idea to add a bit of extra airflow. I have also been in the habit of letting my EP aircraft sit and idle for a few minutes after flying just allow a bit of a cool down period as well. I have also looked at the .60 T-28 link you posted, I'm very impressed with the look of it but looking at the photos the kit it did seem to have a complete set of decals???

Starks

Bellakelpie

Both the big and little kits are short some "NAVY" decals. The little kit does not have one for the underside (or topside if you go that way) of the wing.
The big kit is short 2 x "NAVY" decals. One for one side of the fuselage and the other for one of the wings. If you have a close look at the photo's of the completed .60sized model in the review, it only has "NAVY" on the left hand side of the fuselage.
It was easy to have them copied (size and font wise) and some vinyl replica's made.
The other thing (and this is only a personal bug) is that the shade of blue used in the supplied US "Stars and Bars" decals in the kits, (big and small) are too light. It should be Navy blue, not Royal blue. So a few extra $$$ for a decent set of Major Decals was , in my humble opinion, worth it to finish the bird off.
The attachment is mine with the "Major Decals" Stars and Bars applied. I had not picked up the NAVY vinyl decals from the shop when I took the pic. The Fin decals were pinched from a left over sheet of decals that came in my "Phoenix Rainbow" kit. The cowl numbers from my "Phoenix Tucano" .46 "oily" ARF.

Starks

Yep you're right again, Now that you have pointed it out the supplied ones are heaps lighter, it is a little annoying when there is a lack of attention to detail...... But all-in-all I am still happy with the end product and it is a joy to fly.

Starks

Bellakelpie

And I still cannot get mine up in the air due to the lack of a battery!!!!!
Glad to hear though that they fly nice. Thanks Starks.

iFLYrc_Vic

I left a message on the Hobby People web site to notify me when they get the BlackHorse .32 T-28 E in stock. They have it listed but Not In Stock.

lowbubba

If your are interested in the BH T-28 EP, I just got off of the phone with Hobby People. The said it should be in on 9-19-2008. They have 24 already spoken for. The item number is 159551 and the phone is 1-800-854-8471. Hope this helps.
Randy

iFLYrc_Vic

I am very interested in this plane as my first EP Warbird. I would certainly loved to here some more flight reports before I make the commitment to by. How are the slow flight characteristics?

Starks

Hi Guys,

I have posted a few photos of my Black Horse .32 T-28 flying in my home gallery. I intend to post some more soon...

Bellakelpie

Did some prop tests and got the following results.

Battery Zippy 4S1P 4400Ma/h pack 15-20C

ESC 40 amp Hobbywing

12 x 6 JXF Prop 34.4 amps @ 9200 rpm
12 x 6 APC"E" Prop 38.4 amps @ 9000 rpm
10.5 x 8 Aero-naut "E" prop 24.6 amps @ 9600rpm

I will be trying out a Master 11 x 7 3 bladed prop later.

The ESC and battery remained cool throughout the test session

Max efficiency band of the MVVS motor is 25-37amps


Max amps for the motor is 45 for 60 seconds.

Interesting to see that the JXF prop gives better results than the APC "E" prop.

I have found , when dealing with larger sized props, that stock I.C. props often result in 2 or 3 amps LESS current draw than an identical sized APC "E"prop
My Hobbywing ESC had a balance connector on it , which is connected to the balance charge plug on the battery along with the battery being connected to the ESC via the normal Deans Connector.


When the battery was connected in this fashion, the motor would cut out after 5 or 6 seconds at max rpm.
I disconnected the balancer and just left the battery connected via the Deans Connector.
The motor stopped (the annoying) cutting out at max revs habit.
I have removed the balancer plug harness from the ESC.

Bellakelpie

iFLYrc_Vic- check out Stark's comments re the flying characterisitcs of this model. He gives it the thumbs up.

Starks checked out your T-28 pics in the gallery- nice.