Bugalooob

I went out today and had an instructor maiden my trojan, it didn't go well...It has a O.S. 91 4 stroke with a 65 inch wing...The instructor did the taxi test and all looked good, then he went for take off...This thing shot straight and it was hard as hell to control, it hovered over the pit area and everyone was runnin for cover...He finally got it back to the field where it crashed into a fence (minor damage)...You might say its tail heavy but its balanced at 4 1/4 from the leading edge like the manual says...I even made it a bit nose heavy...The instuctor did increase the travel on the elevator throw by a hell of alot before the flight ( He said he likes alot of elevator, I don't)...I think he might have over controlled it , what do you guys think?

mimoore67

My Feedback: (51)

I vote tail heavy!

Chad Veich

My Feedback: (60)

It's either tail heavy or waaaay out of trim and the pilot over controlled in my opinion. I rarely trust the CG recommendations on ARF's as they are wrong as often as not. On warbird types I like to start out at around 28% of the total wing area and adjust from there. I also always dial in a bit of down elevator on a first test flight to keep the airplane from lifting off before obtaining flying speed. Last, but not least, I like to start with all control throws set to moderate throws on low rate with high rates set in case they are needed once airborne. I've seen too many airplanes wrecked on test flights because the control surface deflections were set to rediculous amounts and the pilot over controlled in an out of trim situation. Very often it appears exactly like an aft CG situation with the airplane all over the sky!

squeakalong

My Feedback: (8)

Sounds like the instructor should have pushed the nose down and headed for a landings..quickly. If the plane was tail heavy, and I wasn't there so don't know, but if it was then all that extra elevator would lead to BIG problems. I'd have pushed the nose down and steered with the rudder for an immediate landing.

Hey mimoore67...I used to fly with the Irish Hills gang a long time ago at a grass field just East of Brooklyn. LOTS of fun there! Is Bill Lent (think I got that right) still around? Tell Him Joe said hello and ask him if he remembers me flat spinning my Sig KIWI into the corn field 'cause both of us were laughing so hard and I forgot who was flying the plane as we counted the spins[X(]!! Didn't really do much damage at all in that tall corn. Lots of good memories out there...er...down there (from here anyway)

Soft landings.

Joe

ram3500-RCU

My Feedback: (221)

Sorry to here this. Very disappointing for sure. Hard for us to tell, not having been there, but it does sound like a very tail heavy plane. I like to balance with a dry tank for the maiden, then I know she is a little on the nose heavy side. I also use expo for a better chance at getting her to trim before something bad happens. Maybe another test pilot for the next try.

perdo

My Feedback: (61)

THe Bh T28 CG was misprinted on the instruction. I don't remember the thread but about a year ago it was it was dicussed and Hobby people even admitted the problem, it should be an inch or two inches closer to the nose. which if I remember is on the Mean Aerodynamic chord.

But it has a been and year ago and I do sleep.

Don

LDM

My Feedback: (15)

I just bought this plane and I typically use 25% of max cord near the fuse , however there is a very long build thread and everyone in the thread and that I have Pm me swears the plane is a cream puff to fly , a gem on the ground and the best value you can get .
The CG was stated to me "follow the plans there dead on "

The only repeated suggestion I received was replace the steering wheel strut (its sucks ) and either add down thrust to the engine or the tail because the plane will clime in its stock configaration

JimO

My Feedback: (7)

Sounds like over control I used the settings as listed in the instruction and used high and low rate at 50 %. If you takeoff to quick it will be hairy as **** to control. Needs speed on takeoff and landing to not snap. Alos likes flaps on landing to keep her steady. It is a real great flyer so not sure why all the issues.

JimO

Bugalooob

I bought the plane used without servos and engine off the rc classifieds and the guy said he flew it like 10 times, I asked if the CG in the manual was right( I had problems with other planes before) ..he said it flew great at the exact CG in the manual...I used the same downthrust angle he had on the plane,...I don't know whats going on with it, I'll move the CG ahead a bit and see what happens...I still think with all that elevator he overcontrolled it

JimO

My Feedback: (7)

How much throw do you have?

AncientCityFlyer

Flew mine with a Saito 82, balanced per instructions, throws set per instructions, maiden was piece of cake. It took 2 clicks of down trim and 2 clicks of R. aileron, flew hands off no problem. After I got familiar with it I increased the throws quite a bit and it became very sensitive to elevator control. Sounds like he over controlled it to me. Just my $.02. Mike

ronwc

My Feedback: (404)

I've seen too many people claim they are a test pilot, and then wreck someone else's plane. In some cases it's overconfidence, and in some cases it is a pilot who's skills have deminished for whatever reasons. It sounds like with your plane it may have been a combination of too much elevator throw and pulling the plane off early in a stall -

LDM

My Feedback: (15)

Please remember , what ever the reason , we are hear to help . I dont want to see anyone crash for any reason at all .
I hope its repairable , if so please look at the very long post on this plane on RCU .
I am doing the same thing as I start my build

balsabuster2003

The airfoil on the elevator is VERY effective. Don't need much throw.

Delta3

Hi Guys,

I have a couple of these planes, the smaller version which had a 52 FS in the nose and the 91 FS version we are talking about here. I had no problems with the C of G but the plane is way overpowered with a 91 FS motor. I had a TT 91FS in mine and if you used more than about 60% power it was a pig to fly. It would do all sorts of silly things. Once the power is evened out to around 50% it flys very nicely. Does require plenty of runway to get it into the sky but flys pretty well once airborne. My opinion is that this bird would fly nicely with a 72 Saito or something similar in the front. I had the flaps set up on mine and it was only for looks I never used them or needed to use them. The flaps were just a waste of 2 servos.

I lost mine when someone came up from under me and cut me in half, but I have another 91 size in a box under the bed and a 120 size Trojan in the garage. That has a Saito 150 FS sitting next to it so when the time comes that will be the engine going in to it, now if it is overpowered with the 150FS I will cut it back to a 120FS andsee if it performs better.
As for the 91FS version if you have a 80FS or even a 72FS try that engine it may prove to be a better mix because with a 91FS this bird is grossly overpowered.

Delta

Warbird Joe

Sounds to me that your instructor isn't much of a maiden pilot. Sorry to hear about the mishap. As far as the plane shooting up. The plane has a nose up attitude with the standard wheels which is causing it to shoot straight up in the middle of taxing. You have to get a smaller nose wheel and a little bit larger rear landing gear wheels. I think we have 3 1/2 rears and 1 3/4 front wheels. Take a look at this [link=http://www.rcuniverse.com/forum/m_7580738/mpage_1/key_/tm.htm]BH T-28 Building Thread.[/link] It has a wealth of information from all of us BH T-28 owners.

This plane handles like a gem. The 91 is a big engine for the plane and definitley is a lot for this light 60 size plane. However, it isn't going to make the plane fly like crap. I would recheck the CG, take a close look at the nose up attitude and get it lowered, and set the throws as the instructions say. This plane has a lot of action with the set throws. There is absolutely no reason at all to do anything different. Oh yeah and get a new person to maiden your plane.

Joe

maukaonyx

I can't overemphasize the need to add down thrust to the engine or it immediately wants to climb way too steeply when full throttle is applied during takeoff. I built a downthrust plate on the firewall at the getgo, which is about 1/8" thick at the top and paper thin at the bottom, to fit right behind the engine mounts. CG per plans was a bit too rearward on my first several flights, so I changed from a 4.8V to a 6V battery and moved it right behind the firewall from its original placement near the recommended CG. The plane will be a kitten after you make similar changes. Good luck and enjoy it! Jon

LDM

My Feedback: (15)

agree with the last few post , every thing I have read is that this plane was a gem , and it simply needed some down thrust and a new front gear leg and also some smaller wheels on the front , all fine tweeks (not ones that will be needed to save the plane)

Something else is wrong , one thing in defence of any instructor , they trust that the cg , and the lateral balance is in check , batterys charged fully , ect ect .
Instructors can visually see bad things like poor connectors , clevises ect , but they usually cant see CG problem , incidence problems , engines that were not broken in properly , they trust in the owner for that .

JimO

My Feedback: (7)

Being an instructor as well as a test pilot for many a plane in my 38 years, I will ask to see the inside of the plane before flying it. I agree you can't everything but at least you gave it a look. I also ask about the CG and it's location, a simple finger pivot check has saved many a plane. If I am assisting a student from build to flight, I have him or her mark the CG on the wing or fuse so all that might fly them have the reference. We all know we tinker with things, even though we don't need to, can make a difference in the next time out to fly. How many times have we had a student tell us I did this or that, why because they can and will. We all do it.

The 28 is a great flying plane as all have said here. Take the time to go over it again, make the changes recommended, tell your test pilot what you have done and if he is not sure, look for a new one, or go for it yourself. Have another pilot that might have better skills than you stand by you to help set trims if you are not comfortable. Taxi a lot, high and low speeds down the runway to get her feel, before you know it she will be in the air and you can feel good about her flight. Treat her like the lady she is and she will do all you ask including the landing.

My 2 cents.

JimO

DocYates

My Feedback: (102)

The design of the T28 is such that it has a long tail movement. It is much like a pattern plane and does not require a huge amount of elevator to be effective. I would go back, put the recommended throws in the model, add a little expo to the high rates, recheck the CG, and make sure nothing is loose inside like a battery pack or something that could have moved during the taxi. This time don't let the TP just gun it and take off, ease nto the throttle and let the plane reach take off speed and then ease into the elevator. There is no need to snatch one off the ground on a test flight (not that he did, but am speaking from experience).
The T28 is a good design and generally when balanced correctly they fly very weel, but you don't need alot of elevator or rudder throw in these models.

NM2K

My Feedback: (14)

It sounds like you got one of those self appointed "flight instructors" that I ran into some years ago. You know the type - badge proclaiming they are a flight instructor, etc. Problem is, all ours were good at was crashing other folks models. A decent pilot would not have been caught by surprise with a model hanging over the pits in a hover. Sorry, but sometimes you have to tell the truth. I'd find someone else for the next test flight.


Ed Cregger