Guillows Stuka

[Erfolg]

I have a kit for a Guillows JU 87, which I wish to build as RC.

 

I am sure that it has been done before. How is the question?

 

Being 34" span, I guess it is built as a one piece model? So is the top front area made removable, to allow access to Rx and batteries etc.

 

I am also concerned with respect to the wing, although it is described as Free Flight or U-control, the highly tapered wing appears to have no washout. I guess it should have washout, how much?

 

The aerofoil is completely flat under-surface with the LE falt to board, therefore highly cambered with a relatively small radius. What was done? Were these aspects changed?

 

The wing is a multi stringered affair, quite different to the single spar capped stripped, "D" boxed affairs typically used. Again was this changed.

 

Finally I would like to use ailerons for roll control. The JU87 has dangly slats at full sized, was any attempt made to replicate this feature, or was a conventional in set aileron used?

 

Any Guillows conversion info will be most welcomed

[Shane Sunday]

This here should help you a little. I'm building the corsair. and these threads are invaluable.

 

http://www.rcgroups.com/forums/showthread.php?t=827861

[Erfolg]

Hi Shane

 

The Index page to Guillows models is impressive, the shear numbers of conversions achieved.

 

At first I was all but putting the box into storage, when i saw the specialist RC gear used, then realised that Nr 508 is only 17" span. Looking at the Nr 1002 model, was more reassuring in the doability stakes.

 

None seem to mention any washout or that the wing section being changed. It is noticeable though, that not one video seen so far has one landing, all flying quite fast. But they do fly!

 

It seems I will have to read all the threads, to potentially extract the information i would like.

 

Well done, good links.

 

[andy watson]

There was washout in my 80" stuka, but I'm afraid I can't tell you how much.

 

Absolute definate  tip stallers without it by all accounts.

 

No idea if this is a help or not.

Edited By Tim Mackey on 07/10/2011 21:14:37

[Simon Chaddock]

Erfolg

A true flat bottom section, particularly with a sharp nose radius will stall more violently and at a lower angle of attack than a properly cambered section with a more generous nose radius.

The absolutely flat bottom wing is of course easier to build and to keep flat. An important feature in a free flight plane with no pilot input.

Similarly its stall characteristics are not so critical if the plane is properly trimmed and then left to its own devices.

 

I would suggest the simplest solution would be keep the flat build wing but replace the leading edge with a more generous sized section of at least 1/3 the wing depth. The result will not be an ideal aerodynamic section (neither was the original!) but the generous nose radius will delay the stall to a higher, more obvious, angle of attack as well as giving a gentle stall.

 

[Shane Sunday]

One of the things a lot of these gys have done is raise the incidence by a mm or two at the leading edge. I haven't started on the wing with my F4U Corsair yet but will be raising the leading edge by a mil. But it just goes to show that it can be done. time consuming lil buggers tho.

 

Glad I could help.

[Tony Bennett]

i have their spit sitting in the loft waiting to be built.

that will be 3 channel rc and electric motor one day.

[Erfolg]

I am grateful for the thoughts and links to RCGroups.

 

I totally agree (as suggested by Simon and Andy) that the highly cambered section are probably fine for free flight and CL, but have characteristics which are not best suited to RC.

 

As suggested I have considered that a good solution would be to use a pre-moulded LE and raise the detachment point, then blend the front underside into the LE.

 

I also have a Thunderbolt kit, which could be a better bet. Particularly using this Thunderbolt link, as a pointer.

[Shane Sunday]

Erflog. Have you started the build yet? Are you going to have a build blog? I've got the fuse built on my Corsair as well as the tail feathers. I was considering posting a build thread. How do you plan to cover yours?

[Stephen Jones]

Hi guys ,

 

I have built a Guillows P51 for rc flying and as i decided it would need to be a little bit stronger due to the extra weight it would be carrying i decided to cover mine in brown paper and poly C worked very well improved the overall strength of the model and did not add too much weight . model also flew well but being a small model only suited for clarm days .

[Erfolg]

Hi Shane, it may be an idea to combine our efforts. It could be interesting to contrast our approaches, why we have done, what we have done. What do you think?

 

It will almost certainly be the Thunderbolt which I will build.

 

I probably will go along the finishing path of Stephen in principle. Using glass cloth, and WBV, partly because i have got it and also it seems to work as well as Tissue and dope (which I don't have, and is increasingly difficult to source without a long journey).

[Shane Sunday]

Ah Stephen I would love to see that bird. Is it still flying? Erflog, you should definitely build The thunderbolt it is supose to be one of the guilows models that converts very well. One way to deal with the flat bottom wing that I saw someone do was to add strips of balsa on the wing ribs so they could be shaped and then covered. I plan on this with the Corsair. I'll take some photos tonight and start a build thread. Feel free to join in. This should be fun.

[Shane Sunday]

Erfolg. Boy I've been getting that all wrong.

[Stephen Jones]

Hi yes still in flying condition although i have taken the ESC out for an outher model .

 

Edited By Stephen Jones on 15/10/2011 18:05:51

[Stephen Jones]

Edited By Stephen Jones on 15/10/2011 19:12:49

[Shane Sunday]

Wow that's cool man. Did you sheet the entire model with balsa then cover with paper? I've atempted to cover the vert stab with solar trim. It's not the greatest job as I don't have much experience so a bit wrinkly. Working on the wing as we speak. Photos some time today if the computer co operates.

[Stephen Jones]

Hi shane ,

here is my posting on how i used brown paper and poly C

linkhttp://www.modelflying.co.uk/forums/postings.asp?th=37460

 

http://www.modelflying.co.uk/forums/postings.asp?th=37237

I did add extra balsa around areas that would need more strength like where the wings are attached if you look at the pictures closely you will see where i have done this .

1/16th sheet was added between the longerons   by placing the sheet over the area and using a pin too score out the shape needed then this piece glued in place and so on .

Edited By Stephen Jones on 16/10/2011 10:16:27

[Shane Sunday]

Here is how my Corsair looks so far.

 

[Stephen Jones]

Hi Shane ,

 

That looks like a strong enough structure to take radio to me but i would still add brown paper as i did which will help stiffen up the wings and fin .

And just add a little extra balsa sheeting around areas of stress . Keep radio gear light and try not too add extra weight by temporary position all the gear to achieve the correct CoG .

 

Keep us posted i love these stick and tissue type models ,

What wing span .

 

[Erfolg]

This has taken me aback, I had thought that the brown paper went over a balsa shell. I had thought. seems a trifle heavy, though I thought it would be strong.

 

I now see it as an alternative to tissue.

 

On slightly different topic, I would expect the Corsair to be the best configuration for a viable model, having broad wing tips.

 

I have noted that the Thunderbolt model "N" has a better wing plan form than other variants.

 

Model N.has a Seafury type of plan form, as apposed, to the Model D below

 

If you click on the image, it goes to the correct proportions. It looks fine on the notepad, bit strange, but at least an image.

Edited By Erfolg on 17/10/2011 19:15:15

[Shane Sunday]

Have you started the Build yet? I have a 63" Jug in the process of getting radio gear. I have started to at balsa plates in all the required spaces for strength. Having looked at your build has helped thanks. I was thinking of using solar film for covering tho. Hmmmm haaa. I dunno. I will be keeping it in mind. At the moment I'm wondering what to secure a spruce square rod to so I can mount a motor to it. Also this will help in balancing the model. This is my thinking tho I could be wrong.

I'm playing with the idea of using bell cranks for the ailerons. I'll have to make them from thin ply. I've had absolutely no luck with snakes.

 

What are your thoughts guys?

[Stephen Jones]

Hi Shane ,

 

I used thin wire and 1/16" ply bell cranks to operate the ailerons on my Guillows p51 setting both ailerons up slightly as i had seen free flight guys do this to in prove the models flight seemed to work ok for me . the elevator simple ply horn via thin wire to servo .

If you watch the video you should be able to see it working .

 

 

Edited By Stephen Jones on 17/10/2011 22:17:00

[Erfolg]

I have just looked at the plan of the Thunderbolt, and immediately spotted that there is the outline of the "N" version.

 

As small models need all the area they can get, this is the version I shall build.

 

I am still debating if to permanently attach the wing and create a hatch for internal access, or go with the removable wing. Just undecided, each has attractions.

[Erfolg]

I have now spent about an hour cutting free the body formers.

 

Very reminiscent of the old KK kits, which were die cut. It is easier now, I have a scapel, rather than an old razor blade.

[Shane Sunday]

Hey there Erfolg. What glue do you plan on using? I am using CA. I don't know if it will work overly well as it doesn't have much fill capacity but it sure has sped up the build time. I'm concidering hitting all the joints with aliphatic before I skin it. Careful with CA glue cuz it will bond your fingers in a second. Ask me how I know So if you go that route make sure to have some un bond handy. The structure seems strong enough tho. Also a handy tool when nipping those notches from the ribs, formers and stringers is a pair of modelers side cutters. You can see them in the photo I posted. It saves so much time.

 

Looking forward to seeing some build pics.