Gee Bee Model D

[Erfolg]

It may appear that this particular build has ended, although not finished. I am a lot slower than many, in this respect. I have partially assembled the model, that is with the motor in place, UC, plus spats,wheels and servos, in their approximate positions. The nasty surprise is that the model is very heavily nose heavy.

Having built in the Lipo tray very much as far forward as possible. this was a major disappointment. Initially as i have normally done this later, this time I have spent time and materials early on. all to no avail, so it seems. Whilst out flying today, i have considered, how can this be. My initial conclusion is that the tail moment is small. The nose roughly what i would expect.

I am now considering how to move the servos and Lipo about, in such a way that the model functions, as a practical layout, to achieve the CG specified.

I will post a few photos to show up the issues, in the near future.

Edited By Erfolg on 03/06/2017 21:29:57

[will -0]

Argh, that sucks!

I've had this happen twice before, once on my chilli breeze which has a lump of fibreglass coated lead screwed to the tail skid plate, once on my NB4 which I got away with just putting the rx pack as far back as I can get it. Always a surprise given it's usually the other way round

 

How much weight needs to go into the tail to correct?

Edited By will -0 on 05/06/2017 13:13:08

[Erfolg]

It may seem, and it does seem, that I have done much on the model. I have done work, although not much. I have been over come with indecision.

These issues of indecision range range from the spats, and how to progress them. The first was how to join them. The second is how to mount them.

The other issue is the CG, although I have attempted a trial balance, which indicates that the Lipo needs to be towards the back. I find it hard to believe. I need to redo this trial.

The other thing that has stopped me, is the lack of a high wattage soldering iron, with a big high mass tip. I need to solder the UC wires together. Most importantly, to me, is to put a little energy, that is increase the temperature of the wire by as little as possible. The basic reason for this is that processed metals have a nasty habit of changing their characteristics, when heated as most definitely in welding, where even soldering will temper the region to some degree, particularly if a lot of energy is put in. I am sure we all know that in welding the material immediately adjacent to the weld (the HAZ) will normally see a coarsening in grain structure and so on. Of course the effects are nowhere near as dramatic, with soldering drawn steel. What worries me, is that not all my landings a feather like. Particularly when i start to think I have landings sorted, Then I find how wrong I can be.

Another aspect that has stopped me is that i need to put the control runs to the elevator and rudder in. I want to use new cables. These had to be bought, the nearest MS is 33 miles away. I went today. My intention was to use Sullivan Golden Wire. Examination of the product highlighted that my memory is pretty poor, as it is so light that a lot of support at either end would be an absolute necessity. Not at all as i remember Golden Cable. Instead i have bought Golden Rod, rather big and clunky, but better that than a floppy end arrangements.

I can only laugh, I take far longer than the 10 hours build, just debating and worrying with myself, as to the best compromise. My daughter (No.1) and son-in-law are both doctors, it is times like this that I understand why they can worry so much about medical issues. The more you know the more you worry, ignorance is often bliss.

[Erfolg]

A change of plan, I have not been successful in obtaining access to a old fashioned high wattage, large tipped soldering iron. Having also searched the Internet, i have concluded that so few have need of such a device in this day and age, no one makes them any more.

After discussions and chatting with club mates, an alternative strategy has emerged. That is to use a blow torch, to waft it over the jointing area. The important aspect, is to attach heat sinks immediatly adjacent to the joint, to act as chills. This should limit the damage to the processing properties.

A club member attaches heavy dutiy pliers with elastic bands to keep them closed. I now need to collect 4 of them, two per side.

Although I would prefer the big soldering iron, the chills are the obvious, although not to me, solution.. I guess it all stems from my training on jointing, where for some joints were done with heavy duty soldering irons, and they were heavy duty back in the day. Others were dipped, ladelled and so on. i guess no one does jointing by any of these means today.

[Erfolg]

I have not been totally lethargic recently. Although progress is slow by many peoples standards, pretty much the norm for me. That is the nearer completion I get, the greater becomes my concerns with respect many of the completed aspects and those still to do. What should i do for the best?

I have concentrated much of my model time on getting the CG in the right ball park, without needing lead. The model feels heavy, if correct, i want no more than the necessary weight to complete as per kit.

The lipo is at the back of the cabin, which is very unusal with my models.

I have now turned my attention to the spats. Initially to the question can I get them on and off in one peice. It seems possible. The next issue is how to attach them. I have come to the conclusion that there will be limited movement of the UC wires, due to the triangulated upper potion to the leg. Any movement will be in the lower part. Does this suggest that the spat can be rigidly attached. Then it becomes necessary to allow the wheels to move back and forward within the spat.

My next issue is that I am awaiting the pilot figure, so that i can make a shorting plug and a harness.

[Erfolg]

It might seem that i have given up on the model.

Indeed, I am still undecided on how to deal with the spats.

My attentions have been, albeit at a low level of commitment on the instalment of the snakes and now the electrics to power the model.

I have now just about got the shorting link sorted out. Not as neat as I hoped, but for me functional.

I felt a little like the Red Queen as I cut of her head, Perhaps I should have listened to the door mouse and "feed my head". Anyway it was of with her head, for better or worse.

I have fastened both halves of plugs in their respective halves. Although I have not managed to get a perfect, just an OK joint, I am reasonably happy.

I decided on shortish tails with bullet connectors, to permit some level of options when completing the power harness.

I will now re-enforce the cockpit floor, to take the forces of connecting and disconnecting the shorting plug.

Still cannot decide on how to instal those spats.

[Erfolg]

It might seem that i have given up on the model.

Indeed, I am still undecided on how to deal with the spats.

My attentions have been, albeit at a low level of commitment on the instalment of the snakes and now the electrics to power the model.

I have now just about got the shorting link sorted out. Not as neat as I hoped, but for me functional.

I felt a little like the Red Queen as I cut of her head, Perhaps I should have listened to the door mouse and "feed my head". Anyway it was of with her head, for better or worse.

I have fastened both halves of plugs in their respective halves. Although I have not managed to get a perfect, just an OK joint, I am reasonably happy.

I decided on shortish tails with bullet connectors, to permit some level of options when completing the power harness.

I will now re-enforce the cockpit floor, to take the forces of connecting and disconnecting the shorting plug.

Still cannot decide on how to instal those spats.

[Bob Cotsford]

now that is an ingenious place to put the shorting link!

[Alan Hilton]

Hi

I have a Dennis Tapsfield chilton plan which shows wheel pants attached with springs running inside the pants hooked to the pants and wings .I haven't built the model yet but it looks a good method .I had an artf geebee a few years ago with the spats hard mounted ,they got tatty quite quickly on our grass strip

Alan

[Erfolg]

It seems that I have not worked on this model for ages, in that very little apparent progress has occurred. I have hinged all the surfaces now, thats about it.

It has been at first sight indecision, the reality is I had no idea of the best way forward at a fundamental level, no indecision, in that I could not see a realistic solution. So i did what many people do, put the thing to one side. I did keep churning what ideas that had been suggested over in my mind.

There was the Gordon Whitehead springs. Then the suggestion by Danny Fenton. Plus a set done by Dwain Bidly. Fially i came across an old Chris Golds build in Model World for a P26 Peashooter.

After considering all of these methods and ideas, I have decided that i will try and emulate the ideas and methods advocated by DF, DB and CG, which all seem to form a cuff at the upper end, some rigidly attached, others semi rigidly using an elastomer (silicon) to absorb some movement. The triangle in the under carriage i will fill in, using light ply, so that that I can secure the spats a little lower to the UC, again using the idea of a little flexibility. The halves of the spats I will tack with the elastomer. The whole idea is to facilitate maintenance and the possibility to replace the moulded spats with balsa spats if the model lasts long enough that it becomes an option to maintain appearances.

It could be some time before I am ready to cover, as I suspect that this plan will take me some time to implement.

[Erfolg]

Although my progress has slowed, progress never the less is being made.

I repeat ably make reference to photographs of the P26 that Chris Gold had published via RW.

Using what appears to be a concept of having a cup that the very upper section of the Spat is attached, I have reproduced my version.

There is also what appears to be two pieces of sheet metal, which are possibly Spring Steel, attached at approx mid point, probably to help in keeping the assembly, stable and equally spaced around the UC leg.

This is my version

Chris Golds appears to use very small screws to attach the Spat to the cup. This initially was my intention. As with many things, I have since changed my mind. The idea put forward earlier within the thread, possibly by Gordon Whitehead, my present intention is to use Bath Type Silicon Sealant. This hopefully will secure the unit to the cup or spigot, whilst providing a degree of compliance, when subjected to impact forces. The same idea will be used to secure the two halves of the mouldings. I have left a smallish amount of overlapping flange in place. My intention is again to use Silicon bath Sealant to hold these together.

To keep the Spats central to the UC wire, I have some stiff closed cell type foam. which I intend cutting to the internal with of the Spat leg area. I will then cut centrally, partly through, before attaching to the UC leg. This I am hoping will work at least as well as the Chris Gold springs.

Most of the reasoning and objective of the proposed solution is to permit maintenance, whist maintaining functionality. I am ensuing the use of screw, as i suspect on this type of set up the screw shanks would act as points of concentrating stress, in an area weakened by having drilled clearance holes.

[Erfolg]

I have now completed a trial fit of the spats using the cup.

 

I seem to have issues inserting images, I am not sure if it is my computer or the Model flying site?

I have used a semi rigid foam to act as a centralising and compliant spring, where Chris Gold used flat spring steel. My reason being is that I had no spring steel and if I had for my arrangement it would have been a little more difficult.

I intend fixing the cup and spat , additionally joining the two halves of the spats using silicon sealant. Looking at both Screwfix and the Toolstation catalogues, indicates a bewildering range of apparently the same product. Can they all be the same, or are some better for our purpose than others?

Edited By Erfolg on 19/08/2017 12:59:50

[Colin Carpenter]

Erf . Having just finished a new shower fitting , my take on silicone is the more expensive are of a superior quality ! Whether the pound shop ones will do your job adequately I dunno ? Colin

[Erfolg]

To be honest, I never thought of the pound shop. Although I am guessing the quanity provided is small, which is what I want.

Both Screwfix and Toolstation seem to stock lots of different brands etc. What I do not know, other than all claiming to be Silicon Sealant, if they are different to each other.

The one claimed property by some is fungal stain resistance. I am pretty sure that for my application it is not something that i care about.

Another claim is being high modulus or low modulus. Again i am not clear at all, what it means in this instance. Is it Youngs Modulus of stress/strain? Even if it is, would low modulus be better, in that there would be more compliance. Or in my real world, of no great importance. Lack of both experience and knowledge leave me having no real idea, beyond this could be a time for pot luck.

[PatMc]

If you have any aquarium supply retailers localy it might be worth looking at the silicone sealant they use to build glass tanks with. They usually stock smaller tubes for repair & maintenance purposes, I know this silicone is good for making aileron hinges for moulded wing gliders.

[Erfolg]

Patmac

That is a great idea. I hate waste, and could only imagine that the majority of the tubes for those gun type thingies would be going to waste.

The other thing is that the big tubes, are not convenient to use, which suggests i would have to squeeze out a dollop, then spatula smaller quantities onto bits.

I know there is a aquatic outlet at one of the garden centres on the way to the flying field. That is as long as United Utilities stop making life difficult, now in two separate major sites, with little evidence of any work, beyond, loads of fencing. two separate sets of lights, one a 4 way single individual go. Then there are the fraking protesters AAAAAAAAAAAAAAAAAAARRRRRRRRRRRRRRRRRRRRrrrrGGGGGGGGGGGGGGGGGGGGGGGGGGGGG.

[Erfolg]

After much prevarication, a lot of worry and angst with respect to how to use SuperCoverite, I have started.

I have wacked the thermostat up to max. I have not taken the knob of and increased the temperture more as per the instructions, as it reads very dodgy to me. So far at this temp, it seems to work.

I have painted on Balsaloc as per the instructions. Laying the cloth on top, after a few hours of drying, seems to reveal a low tack bond between the balsa and the cloth.

I have only tacked around the edge so far. To date not tried to shrink the material.

Shortly I will start on the other wing panel, to complete the underside.

Not having enough of the Black Baron Supercoverite, I have been looking for a material that is similar, in properties to Coverite, i think that Solartex may be similar, although I do not know. I have used a woven shrink covering previously although, now I have not got a clue. All I remember it was significantly heavier than Coverite. I have also used Litespan, which is lighter and flimsier than Coverite.

A reminder of how it can look, when built by someone with a tad more skill.

 

 

Edited By Erfolg on 13/09/2017 15:11:37

[Erfolg]

I have been surprised today, I had thought that a single roll of Black Baron Supercoverite would just about do one wing panel, with a large amount of wastage.

It was on that basis, I thought i would need about 1 or 2m of Solartex, which I was preparing to send away for, hoping for some feed back, that Solartex and Coverite were pretty much the same. I had identified that Webbies was probably my best bet, for both price and supporting them would help in keeping the Probably the Best Model Shop in the NW going, by my own little contribution. My problem was not just the material, but how much? Not enough and it would be a waste of P&P, to much and I will possably never use the stuff again.

What has surprised me is that one roll has done the wing, with some left over.

I will confess to be absolutely useless at covering with iron on coverings, as well as many other things. What has really surprised me is how good Coverite actually is. It tacks easy, it can be arranged easily without significant wrinkles, then irons on a doddle. Normally I have massive wrinkles, burn through the film and so on. This stuff is a breeze. Its major down side is, it does not seem to be available in the UK, it may no longer be made, as I see no adverts for it anywhere. I just wonder if it is or was prohibitively expensive like so many branded heat shrink materials.

Anyway, I will now start thinking about the body, can I possibly get that out of the remaining roll and left overs. I normally find I need that extra peice of 6" * 6", that I have not got.

[Erfolg]

Looking for feed back, that is advice from others experience.

Although I have used film, tissue and iron on fabric previously, I am somewhat out of my depth I think, with respect to the body.

Using tissue is easy, I have just overlapped smallish pieces, the overlap rubbed back, so as not to be seen.

All my other models seem to have had relatively simple shapes, where I could easily judge how big a piece I cold use, normally very big.

The PT 19 being typical.

This Gee Bee has more lumps and bumps. I was thinking of making paper templates, laying on the cloth to work out, what can be be made out of the material I have and the best orientation of the pieces, relative to the weave. It does seem that there will be more pieces than i would like, with overlap.

What have others done with similar materials?

[Erfolg]

The model is slowly coming along, mainly due to a lack of confidence.

To resolve how much Solartex will be required to finish the model, I have done something, which I do not think I have done before. That is make a set of paper templates, and the done something I have definitely not done, that is to lay the templates on the material I have, to work out the best way of making use of the material.

I was very surprised, in that I appear to have more than enough Coverite to cover the model. Potentially with some left over.

What a contrast with my concerns, should I buy 1m or 2m, would that amount be enough? How very wrong and pessimistic I have been.

My concerns now revolve around how to cover the area where the top stringers run out into the fin area. Just bang on the film, or should I smooth on a small amount of filler that the covering can be stuck to. I have no real idea, of what is the best way forward, not having even considered how others on models such as the Hawker Hurricane, Gladiator et al., have managed the same issues. never mind when I have come across such models, never looked or considered how this type of issue is dealt with. Some say ignorance is bliss, I am certain that they are correct.

[Erfolg]

I have finally finished the covering of the model. The two rolls of Coverite that came with the kit, were more than enough.

I now need to start considering the painting process. Again outside of my experience. Normally my preferred system is doped tissue on built up models and coloured film on open structures.

I guess I need a semi flexible paint. Does standard Acrylics fill the bill?

I know that lots of you have experience in this area.

[Aldo Rebsamen]

Hi,

nice to see a Coverite build of the Gee Bee Model D. I did one in 1989 and i still fly it. Great flyer although a bit havy.

Will follow your build.

Regards, Aldo

I have no clue how to insert a picture, but you can see my Gee Bee in RC-Network thread in post #2.

http://www.rc-network.de/forum/showthread.php/332624-GeeBee-Model-D?highlight=gee+bee+coverite

[Aldo Rebsamen]

Hi,

nice to see that Henry Haffkes designs are still liked. The Gee Bee is a good flyer. Although a bit havy. Mine is powered by an OS FS70 Surpass and is quite fast. Built in 1989 and i still fly it. But it was not a 10 Hours build

Regards Aldo.

[Aldo Rebsamen]

Hello,

here is how i did the wheel-pants. All attached with springs and hold together with a spring and rubber-band.

If i would do it again, i would move forward spring attachment further towards leading edge.

It has lasted many landings on gras. Aldo

Edited By Aldo Rebsamen on 26/09/2017 21:41:33

[Erfolg]

Aldo, are you in Germany? As I can read "rechts" on one of the spats.

To date i have nit fastened my spats on. Although they have been on, without anything other than masking tape holding them on.

I have been agonising over the white or cream to use, and does it really matter.I have noticed that the decal has white, a titanium type white, although I have read that the colour was more of a cream colour.

The blue I hope to obtain via having the Decal scanned and colour matched.

I am modifying my Sterling PT19 at the moment. Having put the Gee Bee on the back burner, whilst I continue to prevaricate.

I really think your build does look the cats whiskers.