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laker500
06-30-2009, 12:55 AM
Hello Folks,

I just finished putting together one of GP's Fokker DR1's, it was my xmas present from teh wife and kids. It is an awesome looking plane. I used ALL of their recomended hardware, motor and battery and mounted them in the recomended positions. I mounted up four electrifly servos and used a hitec micro reciever. I am to the point of balancing this bird and I am highly disappointed to find it takes five ounces of lead on the firewall to get the horizontal stab even near level.

Their drawing in the manual shows it set with the horizontal stab drooping below level a bit but that doesnt seem right.

Am I missing something? Has anyone else had a similar experience?

I plan to email Electrifly and get their input, I will follow up with what I learn from them but really want to hear your thoughts in the interim. Thanks.

thomdoe
06-30-2009, 12:58 AM
that's alot of lead

dbcisco
06-30-2009, 01:09 AM
that's alot of lead

Ditto

thomdoe
06-30-2009, 07:01 AM
I would try to rebalance that plane ! But that's just me

Gohmer
06-30-2009, 11:48 AM
Mine balanced fine. Do you have a battery in it when you are checking the CG?

pd1
06-30-2009, 12:04 PM
I don't know how scale the GP Dr-1 is. The full sized had positive incidence on the stabilizer.
That might account for the stab looking as though it's drooping down at the rear.

The DR-1 should fly tail high, With the stab raise to level, then the wings should be close to level too.

Could you post a picture of the leveling that they recommend?

Paul

Henry Sistrunk
06-30-2009, 01:07 PM
http://manuals.hobbico.com/gpm/gpma1142-manual.pdf

Here you are Paul. Hope this helps. I have the SE5 and Fokker D7 and both balanced with no added weight.

Henry

7car7
06-30-2009, 04:04 PM
Is there a way to move any of your equipment forward? I don't have this plane, but recal seeing a few guys altering the location of some of the gear.

But the question about the battery is the important one. Needs to be in to balance.

pd1
06-30-2009, 04:05 PM
I looked at the manual Henry supplied. The stab does look to be tilted in the illustration.
When you balanced your plane, did it sit the way it's shown on the instructions?

It is an awfully short nose, it might need that much weight.
Paul

WWI Ace
06-30-2009, 04:56 PM
Take it from someone with triplanes. They must balance ever so slightly nose down. Move some of your electronics forward if you need to. Try putting the battery as far forward as possible first though. The triplane is a very hard to fly aircraft if balanced the least bit tail heavy. But once the balance is right and you get used to its manners on takeoffs and landings you'll love it!!!! Steve

dbcisco
06-30-2009, 05:07 PM
You can hardly get the stab wrong, the angle is already built into the fuse in the GP Dr.1.

cocobear
06-30-2009, 08:46 PM
I have put together three of these with no nose weight required. You battery was installed??

laker500
07-01-2009, 12:10 AM
Thanks for all the input.

Battery was/is installed, always good to double check and I did.

The equipment is all installed in the provided locations, battery is about as far forward as it can go. Servos the same, reciever could move further forward if needed, right now it is under the pilot. I am concerned about getting it too near the speed control because of interference. Of course everything is movable if your choose to completly butcher your ARF.

I posted some photos. The one of the plane on the stand is without the extra weight. The ones with the level held under the stab show it with and without the extra weight. And lastly one shows where I am laying the weight to get my reference, which is right on top of the firewall.

So far no reply from Electrifly on the issue.

Any additional thoughts based on the photos?

WWI Ace
07-01-2009, 06:22 PM
What size did you say your battery was? Can you maybe use a slightly larger battery and get the CG right. Then there is no dead weight and you can fly longer because of more MAHs. Steve

Henry Sistrunk
07-01-2009, 07:14 PM
http://www.rcuniverse.com/magazine/article_display.cfm?article_id=887

This review maybe helpful. Balance was right on but flew better after adding weight. Still it is a handfull to fly.

laker500
07-02-2009, 02:32 AM
Below is the reply from GP.

"In most cases, I believe the model may need a small amount of weight to balance. When you balance the model the stabilizer should be level. It does seem like 5 ounces would be a bit more than normal for this plane. However, if the all up weight is between 20-24 ounces the weight would be okay."

The problem with the additional weight it is almost 28 ounces, four onces above their recomended top level. Four ounces overweight on a plane less than two pounds is alot!! I have asked them about replacing the fuselage and tail parts under warranty.

Thanks for everyones help, I will let you all know how things turn out.

7car7
07-02-2009, 04:26 PM
I hesitate saying this, not knowing your flying abilities, or your building skill, (and me not having a DR1) but here goes...

It doesn't seem that it's THAT tail heavy in your pic without the weight. I'd be very tempted if it was mine to add 1 ounce, and just fly it. Keep it somewhat on the slow side to take advantage of the potentially heavy tail. (tail heavy plane can fly slower than a nose heavy plane).

And if it did not fly correctly, I'd strip the fuse and the tail feathers, and put the whole rear on a serious diet. I'm a firm believer that the GP planes are overbuilt, especially in the rear of the fuse. You hardly EVER hear of a broken rear end on an RC plane. At least one similar to these.

I would at least start with the fuse itself - the tail feathers are pretty light, and not too overbuilt.

dbcisco
07-02-2009, 06:43 PM
I would be temped to make depron tail feathers for it.

WWI Ace
07-02-2009, 10:47 PM
You could always try it like 7car7 said. Airplanes are made to fly not to sit. If you do happen to break it you can almost always fix it. Believe me, I KNOW!!! Do you have quite a bit of experience with aileron planes such as WWII planes? No matter how well you balance it these are tough planes to fly. The triplane is not a plane for your relaxing Sunday flyer. Steve

WWI Ace
07-31-2009, 01:33 AM
Hey Laker500 did you ever fly your tripe? Steve

forestbird
08-04-2009, 10:41 AM
nice plane

Percyflyer
08-25-2009, 10:43 PM
Laker 500,

It doesn't appear to be that tail heavy in your picture. I just fingered mine for balance and flew it. It didn't require any weight to fly, but after a flight or 2 I put an oz in it to help stabalize it a little. It will be more unstable than you might be used to, just because it is very short coupled.
And you did get a responce from Great Planes, Cocobear is the designer.

good luck
steve