Harvard T6 rebalancing

[Kevin Rochon]

And you thought it was over:D

After watching some RC planes video (hadn't done that in quite a while) I saw some T6's and got the urge to do some spring cleaning and maintenance on the old bird. As you can see from some of the pics there is some dust and webs and even dead spiders on it.

I decided to move up the engine to be able maybe to reduce the balancing weight from 2 lb. to 1 lb. Even with the 2lb it was still a bit tail sensitive, but it's normal for this type of plane with such a short fuse(wingspan 101" and fuse 70").

So keep watching for future development:cool:

[Sempai-mj]

Nice!
How much did you move the engine forward?
Will you have to modify the cowl?

When are going to fly her again, I'd like to be there and film it.:)

[drgilo1973]

i never saw it in the air , when u want to fly it pls post

[Kevin Rochon]

No haven't moved the engine yet just took it apart, but will move it about 1/2" or so, I have the spacers I used on the first flight after the first repair. I don't have to do much on the cowl just elongate the holes already there, for the muffler pipes and spark plug, it shouldn't show too much.

[Sempai-mj]

1/2" should help a lot with the balance.

So the next flight is when?

[Andrew Fernie]

1/2" should help a lot with the balance.

So the next flight is when?
The last thread for this aircraft, "Harvard Rebirth", went from November 2010 to September 2015. Please don't go for a new record Kevin!

[Kevin Rochon]

Should only last ... euh I don't know a few weeks:confused:;)

I will fly it this summer after getting some thumb practice with my other ones.

[beto9]

Kevin, I am glad to see you are back into "sniffing fumes"! (both from gas, glow or krazy glue)

[mitea_dan]

Les moteurs thermiques…la musique des anges…

[Burning Head]

Kevin, I am glad to see you are back into "sniffing fumes"! (both from gas, glow or krazy glue)

That explain the last CG:p

[Kevin Rochon]

Well who says you can't do aerobatics with a warbird trainer, Bobby Younkin prove them wrong. How about a snap on take off and on top of a loop and just to add spice a rolling circle.....enjoy:)

https://youtu.be/ah3Jwz8veSY


Not sure I will do the snap on take off but the other ones I give it a try for sure.:cool:

[Sempai-mj]

Nice flight, looks like it was filmed with a vintage camera, light tracers through the sky.

[Kevin Rochon]

Nice flight, looks like it was filmed with a vintage camera, light tracers through the sky.

That's because it was from 1993. Bobby Younkin flew until 2005 when he had a mid-air with Jim Franklin in Moose Jaw.

[Xavier]

Very impressive. Now I want a T6 in my collection :-)

Well who says you can't do aerobatics with a warbird trainer, Bobby Younkin prove them wrong. How about a snap on take off and on top of a loop and just to add spice a rolling circle.....enjoy:)

https://youtu.be/ah3Jwz8veSY


Not sure I will do the snap on take off but the other ones I give it a try for sure.:cool:

[Kevin Rochon]

Ok I was able to tare my self away from the guitar to do some work on the Harvard.

Actually I put back everything I took off. I decided I would do proper balance test. I always did it at the club with somebody helping me to hold the plane by the wing tips to approximate CG location. I have a balancer I built a long tome ago when my planes were smaller, all I had to do was to find a booster box to raise it to proper height since it was strong enough, the bird weights in around 30LB:eek: I'll have to see if I can borrow the Purolator scale we use at the office it's digital and probably more accurate then my 30+ year old bathroom scale; plus it's always lying to me:o

So got the plane on the balance jig with no mishap or very close, that thing is hard to handle alone.

As you can see the way the plane is right now (and the way I flew it) even at the back end of the CG it is still tail heavy (the windshield stopped it from going more down) so my dream of taking off 1LB of weight just FLEW out the window:roll eyes:

So my choice either I change the 2LB weight to a 3LB or move the engine forward or both.

The easiest for now is to just do another balance test with the 3LB and decide if that's the way to go. Most of the guys flying this same plane add about that in weight. Also they say this plane need the weight. I notice that a manufacturer of a racing version of this plane(same scale) cheated and elongated the nose by a few inches.

It flew ok with the 2 LB but I could feel it being tail heavy, had to dial in some down Elevator.

[Sempai-mj]

Nice to see you back at the Harvard, could a e heavy brass nose cone/drum you could install....
I have one you could try it, if it works your welcome to it. I don't know the thread size.
It's exactly 1 lb.

[Kevin Rochon]

Thanks for the offer Michael, but my special AT-6 spinner from Tru-Turn cost me 75+$ so I intend to use it;), but I'll keep that in mind.

The bolt is a M10 x 1.25

[Kevin Rochon]

Ok today I decided to do some work. So I figured out the most I coud move the 2lb weight was 1.5" so just had to use a 2x3 to make a block spacer, fortunately I had 2 bolts that were long enough.

So after installing it I reassembled the plane to check the CG and it's still behind the back of CG by 1/4". So I had a 3lb weight and with that it goes to the middle point of the CG.

So I need to decide If I'm going with the 3lb or stay with the 2lb. It flew ok with the 2lb just needed some down trim and now it will need less:confused:

[Sempai-mj]

Ok today I decided to do some work. So I figured out the most I coud move the 2lb weight was 1.5" so just had to use a 2x3 to make a block spacer, fortunately I had 2 bolts that were long enough.

So after installing it I reassembled the plane to check the CG and it's still behind the back of CG by 1/4". So I had a 3lb weight and with that it goes to the middle point of the CG.

So I need to decide If I'm going with the 3lb or stay with the 2lb. It flew ok with the 2lb just needed some down trim and now it will need less:confused:

Can you make an aluminum bracket to extend the weight forward, you might need less ??

Something like one of these?

[Kevin Rochon]

my bracket is ok (old school),but I guess I will try to move the engine a bit forward, I don't want to go with one more pound:no:

[Mezri]

Est-ce-que les sevos profondeur et dérive sont à l'arrière ? Car dans tout les cas gagner 100 gr à l'arrière c'est gagner aussi 500gr (1Lb) et plus à l'avant...parfois changer une roulette de queue peut faire gagner du poids...:)

[Kevin Rochon]

Les servos sont pratiquement au milieu pas vraiment d'espace plus loin. La roue de queue est très légère. J'avais une tige de fer pour tenir le Rudder en place je l'ai changé pour une en plastique...croit moi j'ai tout essayé.

Sans les ailes il est très nose heavy mais les ailes sont swept back donc cela fait une grosse différence.

Je vais avancer le moteur un peu cela va aider.

[Mezri]

C'est vrais...dans ce cas avancer le moteur d'une manière imperceptible pourra aider...bon courage...c'est une belle machine...:)

[jeanyul]

bien hâte de le voir voir voler Kevin

[Kevin Rochon]

So I did some tests today. I installed the spacers I used on the 1st flight after the crash. I temp. installed the muffler upside down so I didn't have to cut the holes in the cowl. With the 2lb weight it is still 1/4" behind the aft of the CG:mad:

Also the prop is pretty far ahead of the cowl. So either I put back the engine like it was and used the 3lb weight or just used the 2lb it will still be better than the last flight, which was ok.

I'll have to ponder on this some more:confused:

BTW I think i'm not running lean looking at the sparkplug;)

[Sempai-mj]

"BTW I think i'm no running lean looking at the sparkplug"

Looks a tad rich, any black stuff coming out of the muffler?

[Kevin Rochon]

Oh yes lots of oil, but I think the gasket for the muffler is not 100% leak proof I might put some high temp silicone also.

[Kevin Rochon]

Well finally finished this week and this PM. I decided to put back the engine as it was and see, it was flying ok so now it will need a bit less down trim, also the gas tank is 32 oz which is a little over 1.5lb and I will never empty it completely probably half.

So now it's back on its feet:) Waiting for good weather....it's a good thing it's a patient plane:rolleyes:

Next patient is the Bigfoot for motor vibrations.

[Sempai-mj]

Well finally finished this week and this PM. I decided to put back the engine as it was and see, it was flying ok so now it will need a bit less down trim, also the gas tank is 32 oz which is a little over 1.5lb and I will never empty it completely probably half.

So now it's back on its feet:) Waiting for good weather....it's a good thing it's a patient plane:rolleyes:

Next patient is the Bigfoot for motor vibrations.

Cool, congrats, let us know when the flight is!:)

[jeanyul]

Coll Kevin bravo bien hâte de le voir moi aussi

[Dwight Macdonald]

Nice work Kevin! I'm sure it will fly great!:)

[Kevin Rochon]

Thanks guys,

BTW for the Bigfoot motor vibration, I'm not even going to make a separate post, actually I'm even ashamed a bit.:o

I took off the spinner and prop tonite and I had a hard time taking off the back washer, that washer rest on an adaptor that's conical and you know what's comical I had put it backwards. So now all is hunky-dory:rolleyes:

[mitea_dan]

Un engine, glow ou gas, de préférence en étoile, va régler les problèmes.

[Kevin Rochon]

C'est un moteur rond avec des aimants tout autour comme des étoiles:D

[Burning Head]

C'est un moteur rond avec des aimants tout autour comme des étoiles:D

Ouin c'est vrais... c'a ressemble a la description d'un brushless:D C'a en prendrais un gros en titi

[Burning Head]

Sérieusement, les cc change tu lors d'une conversion a un radial question torck ou c'est plus pour le réalisme du moteur et le son qu'ils dégagent