Tailwinds:

The black is on top of the yellow. To get the bubbles down you have to ***** them with a sharp #11 blade to let the air out, then iron them down.

Sounds like you were just going hotter and hotter on the iron until the adhesive melted.

Jim

JRF- I know your intentions are to help but what if there is no yellow under these areas? ( don't read me wrong either - I appreciate your efforts and input!)
The plane came with the white crusty glue look - out of the box and I started reapplying with a heat gun with soft cloth.The " lifting and crusting problem" is on all of the black areas- not just a wing panel or top of fuse - all areas.
Again this is the 27% version (97"ws) not the smaller - which may have been covered differently.

It will heat back down but only temporarily- yet the all areas will return in time - in the air conditioned room I use for the hobby..
Sorry and thanks , but ya need git the thinkin' cap on again.

How is the balance with a 1.20 4-stroke? Does it need some weight at the firewall?

OK, I don't know what you mean by "white crusty glue look". Is it something you can post a picture of?

Generally, that "ChinaKote" covering requires an iron to stick it down. The heat gun will smooth it, but you have to go back over it with an iron at high heat to stick it down permanently. When I built mine (97" Red and white) it took me about 4 hours to iron down all the covering, but it has stayed down, except for a little touch up now and then.

Jim

Yes, it will probably come out tail-heavy with a 120 four-stroke single.

Jim

Red & White - There was a good idea.
That white crusty look is just the glue lifting .
Taking a JPEG was easy - uploading on RCU via MAC is another problem.

i have a OS bgx 3500 in my gby ,look at the video,plenty of power. needed a little tail weight

Are you talking about just at the seams, or all over the surface?

Jim

Actually the seams do not have a problem. It occurs in the larger areas of black covering. Top and bottom.
I also spent an initial uncounted hours resealing this planes covering. That is allot of area!

It sure is! I don't know what the "white crusty glue look" is. I haven't worked with the black color before. Maybe someone else can give us a hint.

Jim

I'd be happy to send you the JPEG of it- but I would have to send to your email.
Do you have a hotmail e mail account I could use?? PM me the address if you want.

I have an older A&M 2.0 that weighs less than a G-26, but more than a 4-stroke 1.20. It's about 40oz with an ignition battery, and I was considering getting one of these,(LHS has one he really wants to move out) to put it in. Sounds like it would be a good match, however it would be a good bit overpowered. It will turn a 18x8 at about 6900 or more.
Thanks for the info.

That should work fine. I don't think a pitch speed of 55 mph is going to overpower it though. A 1.20 turning a 16x6 at 9000 would be about the same. The bigger prop on the gasser will give you better acceleration and vertical, but it's speed that kills airplanes, not thrust.

Jim

Can anyone give me the cowwl diameter. If I am going to get one, I will use the OS FT 160 twin, but I would want to keep it all inside the cowl. The 160 turns an 18X6 at 7500 RPM.

Bill, AMAS 4720

Measures 12.25" inside dia.

Stickbuilder:

Tail Wind is talking about the 97" Gee Bee. The 82" cowl is about 10", but I don't have mine here to measure.

OBTW, an 18 x 6 at 7500 is only 45 mph. That is awfully slow for anything other than a Telemaster. I think I'd try a 17 x 6 or a 16 x 8. Doesn't OS recommend about 9000 rpm for that engine?

Jim

Here is the picture of Tail Wind's black covering. Does anyone have a similar problem, and/or a solution?

Jim

Have had my GB-Y for over a year and have maybe 30 flights. Only problem I had was the gear mounting blocks were very open grain mahogany and very thin. I replaced with thicker machined poplar slotted to lock over ribs, epoxyed in place and haven't had any problems since. Easy to fly plane, I use Saito 180 and classic Master Airscrew prop, the combo seems OK by me....... Covering is a little thin, like econo-kote. I would have prefered Ora cover or Ultra cote.

Thanks JRF for posting my picure.
(Computer's back up! I went on vacation and returned to a fried computer logic board due to a power surge - $835.00 repair!!)

Drone Pilot - Is your GBY the 27% (97" ws with black / yellow covering?

My GBY was purchased in Feb -06. The covering came to me in this condition -out of the box.

""The 160 turns an 18X6 at 7500 RPM"".

""OBTW, an 18 x 6 at 7500 is only 45 mph. That is awfully slow for anything""

I would think your going to want more power than that, I have a MVVS 35 in my 82 inch Gee Bee Y, it turns a 20x8 at 7500 and I wish I had more power..

Jim

Hi guys just to add my 2 cents. I got my 82" 3 weeks ago. I built it with minimal problems, except the pushrods were too short and I replaced with 4-40. For power I used a Saito 182 twin. No added weight except for the on-board glow and it balanced perfectly. It flys very gentle.

I am building the 27% paca geeBee (250cm), but I am hésitating between a nice (but heavy) radial motor like the SEIDEL ST710 (2,7kg) and a light 50cc single cylinder 4 stroke that will weight much less (1,6 kg).

So my question is : what is the perfect engine weight to avoid any "balancing weight" in the tail (when the motor is too heavy) or in the nose.
**************



and what make things more complicated is that I do NOT want a motor that has a bad noise and that use lot of oil ! Indeed, I will put on my plane an engine that :
1- use little oil (I don't want any of those messy motor that need 18% oil + Nitro ), and
2- has a NICE SOUND (so supposively a 4 stroke, and may be multicylinder !) ???

any idea ?


Many thanks for your advices.

I would not be concerned of the weight, the plane will handle it. Make sure the servos for rudder and elevator are located at the tail.
Mine GBY (about 85" or 2150mm wingspan) was planned by Pacific Aeromodels for having the rudder servo around CG and proposed to use pull-pull system. I relocated the servo under the stabilizer, was no big job. My Enya VT240 has about 1.9kg with exhaust and blances the airplane perfectly with this setup.

About messy oil: I routed the exhausts down through the tunnel in the firewall and let the pipes protrude about 30mm, there is practically no oil on the airplane.

A nice sound, a reliable engine, not so much weight: Laser 300V or even 360V. You always have to consider, that any model airplane engine does more rpm as the real thing, and this combined with many cylinders will create a sound which differs of course...