Bob Paris

My Feedback: (13)

Hay iFLYrc_Vic,
I am on my way to NAPA and see if I can find some thin gasket material for my strut bottoms-to cushion and allow a little movement. I'm convinced you are correct about keeping the wheel pants movable...if not just for a small bit of movement. I dug through all my old Kraft radio gear and found some neat round grommets to emplace onto my wheel pants, fore and aft, in two places as you suggested-this will float the strut a bit and allow some movement with out damage. I will be rebuilding my left wing I just finished to include all the mods and also looking for small stiff springs.

If anyone knows where I can find small stiff springs, to use in my guide wires...please let me know. I want to add stiff springs to the landing gear, to assist them in being able to move and give a bit-same for the wing.

I'm also considering to modify my vertical stabilizer a little, to make it a little taller and maybe do away with all the Yaw issues some have reported. I may add a couple of inches to it...and add a little more to the rudder also.

This is turning into a more complex build then I first thought...but its gona fly.

Soft Landings Always,
Bobby of Maui

EQ1

The landing gear is definitely the weak point on this bird. The length along with the stiff steel design guarantees really bad landings. Nobody should be astonished if his/her airplane will jump like kangaroo when not set down silk smooth. Therefore, I completely redesigned the struts and applied shock absorbers from RC cars (replaced the spring with a stiffer one), which adds dampening. There is no way to do smooth landings without dampers. Springs take the energy when compressed, but they give it back nearly 100% on release. So we need to absorb this energy, which is usually done by oil dampers. The other point is that the struts, NOT the pants need to be fixed by the flying/landing wires. To do this you need thicker wires than the stock ones. I replaced mine with 1mm wires sucessfully.

Here are some pics of my mods. The costs are really low, about 50$ plus some work.



Concerning the "yaw problem": The large landing gear lead to a significat amount of area IN FRONT OF the cg, which means reduced stability around the yaw axis. This is no problem as long as they are straight and equally angled. Otherwise one gets all kinds of weird flying behavior. A larger vertical tail and rudder would help to overcome the mounting mistakes, but are generally not necessary. Mine flies really nice without any problem. Here is a short vid of it (50cc version):

http://www.youtube.com/watch?v=knCJUCpMyiI Have a nice day!

Ejet42

I have purchased a set of 50cc Oleo struts for my R3 on 10/30/13 from GMP, based on photos in this thread, but they haven't shipped as of this posting. Does anyone know if they come with the heavier wires (pic 5) and what appear to be knurled fittings (Pic 7) for attaching said wires to the oleo struts as shown in pic 8 below from posting #290 (page 12).

Help would be appreciated.

Henry (Ejet42)

Attached Thumbnails

gjhinshaw

My Feedback: (303)

Henry, They come with the bigger wire for the struts. I am waiting to hear from China for a tracking number for the struts.
I am also told that they are send a stronger elbow wire with these... I hope to here from them soon.
Gerry

Bob Paris

My Feedback: (13)

Hi Guys,
The landing gear on the 20cc version sucks...no matter how many times I work on it...it just never seems to get easier. I managed to find springs and I'm going to spring load my landing gear on both sides of the landing gear. I found the correct extension springs and ordered more from ACE Hardware. The springs will take two weeks to get here...but I will have them soon enough. Who ever designed the landing gear attachments on the 20cc size R3, aught to be neutered and or castrated...so not to spread that end of the gene pool. What a joke... : (

I made my main gear strut/wheel fairings able to move a bit, and I used a gasket on the bottom against the wing & fairing to allow it to move more easy, and installed servo mounting rubber grommets w/brass inserts into the fore and aft positions, to hold the fairings onto the wing. The rubber grommets will allow the wheel fairings to move a bit and still hold them in place. I do hope that this solves some of the problems with the wheel fairings cracking and breaking off.

I built my left wing stock...but now need to redo it to match my right wing. After I built my left wing...I didn't like the results at all. The landing gear is so stiff and weak, being so long, I knew I needed to inset some kind of movement into the fairings. The pictures will show what I did.

After I finished with the right wing landing gear instillation I found out that the wheel has "toe out" and I will now have to remove the assy. and bend the wheel axle straight. Oh sweetness, I'm not gonna like this bit of rework.

Does the manual with the 20cc R3 show the correct CG? Any one know or has flown the 20cc size R3 that has experience with this model?

Does the kit build nose heavy or tail heavy...?

Great stuff here and thanks for all your information.

Soft Landings Always,
Bobby of Maui

iFLYrc_Vic

My Feedback: (6)

Good job on the gear wires and springs. My issue with the wires (without springs) was that the hard points were too weak and would probably pull out on a landing that pulled the gear left or right. The springs provide some stress relief to the hard points.

As for the CG, I found my model flew best at about 80 mm from the leading edge vs the 85-90 listed in the manual. The 85-90 results in a slightly tail heavy setup that I did not like.

Good luck,
Vic.

Bob Paris

My Feedback: (13)

Hi Guys,
I finally have both my wings with the landing gear modified, properly installed. You just have to love how the revised 20cc has the landing gear installed...and it took a good couple of hours to do the business...grrr. I then assembled the model fuselage to the wings...just to see how things fit. Well, the top hatch of my fuselage is warped and twisted at the front end and the left wing does not butt up against the fuselage as nice as the right side does. I can get the cowl on the fuselage with the warped top hatch...but the attention to detail is not up to par, with my kit.

I will be modifying the attachment brackets of the inboard landing gear support flying wires, to the fuselage. This will need to be made more stout and I'm going to install plywood plates and using blind nuts and cap screws to hold down the flying wire support brackets. This should give me a good bit more support then the balsa wood now used in my kit. I will do the same to the top wing support bracket area too and with any luck, I'll have the strength needed for my less then perfect landings. Its the best I can do for now and my modifications takes only two screws to hold down the wheel fairings, in rubber grommets. Lots of movement and no cracked fairings.

I am going to enlarge my rudder and modify the vertical stabilizer. I found a picture of one mans modification to the rudder and this should correct the yaw issues with the smaller R3. The pictures I saw brought the rudder up a little higher, above the windscreen...and sloped aft. It looked great and will be easy to do. I want this model to have a good chance of flying with out any yaw issues. The landing gear on 20cc size is problem enough, with out yaw issues because the rudder is over powered by the wheel fairings.

After this I'll install the engine and all its systems. I will have a transmitter operated engine off switch installed, a 16 oz. Roto fuel tank and I'm using HD1501 servos on the rudder and elevator. I've had really good luck with the HD1501 servo's with my Airtronics gear and you can't beat the price. All metal geared, with dual ball bearings, 200+ "/#'s of pull, for under $15 bucks.

What size Gee Bee R3 is the best flyer...does anyone have any idea? Is the 30cc size better then the 50cc size in flying qualities? I'm not real pleased with my 20cc size so far and looking to probably build another...larger version, with Robart landing gear. I love the looks of this model, its most unusual and gets my juices flowing. Does the 50cc size have flaps...?

Soft Landings Always,
Bobby of Maui

iFLYrc_Vic

My Feedback: (6)

Bobby, where did you see the pictures of the modified rudder? can you post them here?
Vic

gjhinshaw

My Feedback: (303)

Yes, The 50cc does have split flaps.

Jetflyer3000

Had the maiden flight on my 50cc version of the GB R3 from HK. Picked it up in the UK for £185 and what good value. I have a DLE Copy 55 cc for power also from HK and she flys like it is on rails. I have quite a bit of lead up front over the engine. All in all very pleased with her and the way she flys

gjhinshaw

My Feedback: (303)

Very nice!!!! Glad you like it.... Yes, the HK one is from our factory..... BUT.... It does not have the tinted canopy, the thicker cowl, It does not come with carbon fiber wing tubes, carbon fiber tail wheel, or a carbon fiber spinner. I also think it doesn't have the better hardware... But all in all it is the same plane.. I am glad that so many get to enjoy a plane that we brought out before everyone else did....
Gerry[


QUOTE=Jetflyer3000;11663923]Had the maiden flight on my 50cc version of the GB R3 from HK. Picked it up in the UK for £185 and what good value. I have a DLE Copy 55 cc for power also from HK and she flys like it is on rails. I have quite a bit of lead up front over the engine. All in all very pleased with her and the way she flys[/QUOTE]

Bob Paris

My Feedback: (13)

Dear Vic,
Here is the only picture I can find with the modified rudder. From what I read, this will solve all the issues in the Yaw axis and came from another forum.
Bob

gjhinshaw

My Feedback: (303)

Bob, You don't need it on the bigger models, for sure....

Jetflyer3000

Mine did not seem to have a Yaw problem it flew very well indeed

iFLYrc_Vic

My Feedback: (6)

I have seen a few other models that appear to have a larger vertical stabilizer. It may help with the yaw issues on the smaller 20c version that we have.

iFLYrc_Vic

My Feedback: (6)

Retired my R3 after numerous attempts to correct its unorthodox flight characteristics. Just flew like a plane possessed! In other words - flew like a mad dog with a disease. Too bad, its such a beautiful plane. I pulled the motor so I would not be tempted to fly it again and have an upset. she is an official HANGER QUEEN....

gjhinshaw

My Feedback: (303)

Is this a 20cc????

mikes68charger

My Feedback: (34)

My 30cc and 50cc were the same. But if you take the wheel pants off it flys like a 540 edge

iFLYrc_Vic

My Feedback: (6)

Yes, that is a 20CC model converted to electric.

gjhinshaw

My Feedback: (303)

Okay.... Go here to do some reading and some help...(Maybe) I hope this MAY help you.....


http://www.rcgroups.com/forums/showthread.php?t=1374474

http://www.rcuniverse.com/forum/elec...ld-thread.html

And a Manual.....

http://www.epower.ch/downloads/Bedie...uts/GeeBee.pdf

iFLYrc_Vic

My Feedback: (6)

The first link is for a guy who "says" he will setup this 20cc plane to fly on a 4S battery power system to keep it light. Well, if you read the entire thread, he never flew it ! Just words. The second link does not provide any useful information about flying this model. I have the instruction manual and used it to build my plane. gjhishaw, thanks for the links but they do not help me at all with this model.

There are many other folks out there that have the same exact comments about the flight characteristics I found in my 20cc model. It is not just coincidence that they have the same problems - its the plane.

One modeler has commented that the problems is the wheel pants. He even said it flies great without them. I am inclinded to believe that is the problem with this smaller version of the plane. They are huge and may cause issues on the small version and not on the larger ones (size to weight ratio). I am no aeronautical engineer, but all that weight hanging down from the plane would seem to account for its unusual flight. I may take the time to remove the wheel pants and try to fly it again. However, the wheel pants are what makes a Gee Bee a Gee Bee.

Regards,
Vic

Condor060

My Feedback: (2)

Hello Vic, I have been watching your post and I might be able to help you with a solution. I have flown the 20 and 50cc models with the very same characteristics that just inherent with this aircraft. My solution was to align the wheel pants so they are aerodynamically correct. This will correct the yaw in flight (if this in fact is what you are talking about) TO the extent of the flight characteristics after alignment the airplane doesn't fly like anything else out there.

First for the alignment portion. I flipped mine on her back on one of my stands in my shop. I ran a very tight string (attached to a wall on one end and a bench on the other) right down the middle of the fuse from nose to tail making sure it was dead center. Then was the process of getting the front center and rear center of each wheel pant equidistant to the string. I was actually amazed at how far off I really was. It is time consuming and a royal pain to rig this up but it worked great and the plane flew like she was on rails after that.

Now for flight characteristics. Once aligned properly the Gee Bee will not fly like other aircraft. For example. When you aileron turn most RC aircraft on their side they will start to turn in that direction. The Gee Bee won't. It will continue to fly on its original path as you now have 3 rudders forcing her to stay on course so lining up with the runway can only be done if (A) you have the right approach or (B) you use rudder to correct as ailerons will not help you here unless you use elevator (once the plane is on her side) to turn.

It is a very freaky feeling to get used too as we all have years of flying with one rudder instead of three, (counting the two wheel pants as rudders) I am not of the opinion that a larger vertical rudder is going to help in the perforrmance issues you are describing here. If anything I would think it would make matters worse.

Anyway, thats my story. I hope it helps you with your Gee Bee. For me she is worth the extra effort as nothing else out there is like her. Not to mention they are great for aerobatics.

gjhinshaw

My Feedback: (303)

Thanks for the reply Fred! Do you remember how far you were off??? I don't remember what you said, been a long time ago...
Vic, I still have lots of parts for the 20cc GB... Wings, tails, and some other stuff... BUT....... No wheel pants or canopies.
I am still trying to get those in..... My last shipment was taken by customs and was later destroyed by them! They said it was a infringement on texaco..... (LOL)
I am in the process of getting them here another way....

iFLYrc_Vic

My Feedback: (6)

Condor, you are the first person who has fessed up and agreed that this plane flies like no other plane out there. The 3-rudder explanation is probably "spot on" with respect to the reason she flies like she does. Misalignment will certainly be a factor in its unorthodox flight. I am grateful to you and thank you very much for providing a solution from experience with the same model. I have gotten very upset with all of the "back seat drivers" who derive solutions for this plane but have absolutely no real time experience with flying it and imply that we lack adequate piloting skills. Some of them mean well, but others just try to toot their own horns. Like the guy who suggest flying a 20cc plane on a 4S power system (good luck).

You have given me reason to put the motor back in it and give it one more try after wheel pant alignment. I might try it without the wheel pants but it is a royal pain to take them off.
Thanks everyone for your comments and help.
Vic

Condor060

My Feedback: (2)

I don't think I would take them off. That is a pain. This is how I set mine up. Run a string down the middle of the fuse just above the body. Maybe an inch. Run a second string above the first string that is at the same level as the wheel pants. Now you have two strings running perpendicular to each other about a foot and a half from each other. Tie two strings with a small weight to the top string and let them hang down about an inch above the bottom string on the front and rear of the fuse. This will align the top string with the bottom to make sure they are exact. Gravity is your friend here.

Once you align the two wheel pants with the top string you have to make sure the two pants are equidistant to each other. This will get them on the same plane of attack equal to each other. You can use some hot glue to or tape to keep this stable until you find that perfect match between the pants being equidistant and the measurement to the string.

Don't worry if the two individual wheel pants are not exactly the same distance from the string. Getting them straight and equal to each other is the point here. You will find that you are a LOT farther off than you anticipated. Believe me, the string doesn't lie.

If you ever liked flying knife edge, this is your ship cuz she'll do it all day with a rudder loop in the middle for good measure. The wheel pants have more force against the aircraft than the rudder does. Imagine them as two very large front canards turned sideways because thats what they are.

It is a completely different style of flying. I have handed mine off to several friends of mine in flight and they always give it back after the first few turns. They don't like it because it doesn't feel like everything else in the world they have flown. Once you get over the initial feel (a bullet with tail feathers) and learn what she wants you will really enjoy the ship. I had a 3W 55 on my 30 size and a DA 85 on my 50 size. Both were just monsters.

Here is another trick I learned. Even with the cables connected to the wheel pants they would still want to move around in flight giving me some weird oscillations. For the bottom of the wing I used thin aluminium tubes instead of cables. One on each side. Flatten the ends and screw them to the front point on the wing where you would connect a cable. Flatten the other end and connect it to the wheel pant. I use cables on the top of the wing (for looks) but used small springs on each cable. This keeps the cable from stretching and becoming limp. Always stays tight and looks good.

I painted the tubes black and they actually look better than the wires do. They will keep your wheel pants solid in flight and landing as well.

The Gee Bee is like the hottest girl you ever dated but gets a little crazy every now and then. You want to show her off to your buddies but you are worried she is going to embarrass you.

She needs extra love and restraints. Then she will be ready for her debut.