August Edition CAP 21 Plans

[Peter Miller]

I have been remembering a few things and talking to some people who have been in the magazine business as long as I have been modelling. These may be of interest in passing.

There was a Model aircraft plan for a scale twin from the early 50s that didn't even show the location of the wing on the fuselage.

The old Aeromodeller offices had a drawing office with 5 draftsmen employed full time. I know that one of them refused to turn his French curve over so all formers were assymetric.

I was told of a draftsman who was so bad that he even spelt his own name incorrectly on the bottom of a drawing.

Not so long ago there was a free plan for a sort of funfly model, it didn't even show the ailerons. I spotted that one.

Interestingly, no one has complained about my Rhapsody plan, probably the most complex plan that I ever drew. In fact it was used without even redrawing just some polishing up which must say something. (I suppose I will get an earful now to say that I am wrong.

As for enlarging and correcting Li'l Mistang. Not much point in correcting it if the draftsman will mess it about again. I don't have the original tracing of that one now.

The person that I was talking to did comment that American plans used to be beautifully drawn anf printed.

[kdc]

American plans seem to be drawn in a much nicer style with more detail. I remember seeing a motor glider plan ( by Pavel Bosak I think ) published in an English mag and also in RC Modeller in the USA. The extra detail was amazing in the US version.

Why are errors in plans not corrected in the next issue of the mag?

I was suggesting that the Lil Mustang is such a nice design that a slightly larger 40 size plan would be nice.

[Peter Miller]

I don't know why mistakes are not corrected. Of course we have lead times. The plan comes out and then it will be a little while before feedback gets back to the magazine afterwhich itcould be another two months before the magazine actually hits the news stands. Even then it could be included. It is an editorial decision and contributors have little influence on that.

I do know that when, after a long time I found a weak spot on the Rhapsody design in the undercarriage mounting I was able to put out a warning but I had to do that through my own column.

If you want a larger Li'l Mustang the best thing is to take it to a big copyshop and get an enlargement made. Someone has just done that with Chantilly Lace. Took it up by 11%. I did a very similar design to Li'l Mustang but based on the Cosmic Wind, it was called Dancing Girl. That was a terrific model. IT was powered by an SC 46. When I tried Knife edge flight I gave it a bit too much rudder and it flew a knife edge loop. I still haven't got over that. Plans are available from Model Activity Press.(A.M.I.)

Plans in the USA do seem to vary. RCM used to produce very detailed ones. Flying Models seem to be about the same t=standard as ours.

Talking of Accuracy, I am a Monocoupe enthusiast. I have the 1/10th scale drawings from Model Builder. The incidence shown on the tailplane is completely wrong and very obviously so. That is supposed to be a highly detailed and accurate scale drawing of the full size.

[Nick Chudley]

I have only built one serious model from plans and they were bought directly from Ivan Pettigrew, who is based in British Columbia. He sells his plans for about £20 each and, in my view they're worth every penny. No problems at all except for the laborious business of tracing and cutting all the ribs and formers.

Consequently, I like the idea of laser cut kits and I wonder why it is not easy to buy these, even on a one-off basis. There are computer programs that can cut straight from a digital drawing and other programs that will digitise hand-drawn plans. By using these it should be possible to cut to order without a major premium on the price. A Google search reveals several companies that appear to do this?

Peter
Possibly this would be a channel for you to supply your plans, exactly as you have drawn and tested, as a "short kit" for a fair price. Free plans are all very well, but, considering all the work and materials that go into a model and depend completely on the accuracy of the plans, I would happily pay the price.

I guess this has already crossed your mind, maybe there are copyright implications. What do you think?

Nick

[kdc]

Cutting out formers and ribs should not really be a laborious task ( for the type of models designed by Peter Miller ) compared to the whole job of building a plane. There are usually about 4 ply formers and a few balsa ones.

The formers can be photocopied or traced and the photocopy stuck to the wood with double sided tape. Then a simple matter of sawing to shape. A very fine tooth saw (tenon saw, dovetail saw or japanese pull saw ) for the plywood straight bits and a fretsaw for the notches and curves. Electric fretsaws are easily obtained for a little over £30 and are easy to use.
Stick the photocopy direct to the balsa and cut right through the paper and into the wood with a scalpel or Stanley knife. The 1/32 or 1/16 ply can also be cut with a Stanley knife. All edges can be finally shaped to exact size quickly with a Permagrit tool. Simple no need for laser cutting! Perhaps a few hours work at most.

Parallel chord ribs are easily shaped if they are stacked together in the classic way and Razor planed to shape (or use a Permagrit tool ) Tapered wing ribs have to be cut out individually but you can cut out pairs by sticking 2 sheets of balsa together with double sided tape. Again use a photocopy and cut right through into the balsa using a scalpel held vertically.

[Steve biplane]

All,
If you are going to cut 1/32 (0.8mm) and 1/16 inch (1.6mm) thick ply with a Stanley knife then take care because there is a tendency press down very hard and you lose control over where the knife goes if (when) it slips. Lots of cuts with less pressure and slowly cut your way through is the way to go. Better still, if it is a straight edge you are cutting, then use a razor saw.
Steve, who sits back and awaits replies from anti-H&S brigade.

[Peter Miller]

Steve. Plywood is cut with a freet saw, power or otherwise.

be back in aminute to answer the others

[Steve biplane]

Peter,
I agree but in his post preceding mine kdc says "The 1/32 or 1/16 ply can also be cut with a Stanley knife." and that is what I was referring to. (and let's be honest haven't most of us done it at some time or other) but that doesn't mean we should advocate it.
Steve

[Peter Miller]

True. I use snips for 1/32nd ply quite often or tape two pieces togewther and saw them.

Greeairdesigns.com will cut you a laser cut kit. There was was a company called Bellaire or Belair in Norfolk up until recently. They also did laser cut kits, I just looked on google but couldn't find them....Look in the mags or search the internet.

Why don't I do short kits? No thanks! I just design and build models that I want for my self and then send the plans in, no hassle, no organising. At my age I am not interested in a business thank you.

As I have said several times. I do the best that I can and will hold my hands up if I make a mistake. Please don't complain to me, complain to the magazine.

[kdc]

I find it perfectly satisfactory to cut ply with a Stanley knife, but obviously everyone can choose their favourite tool.

Perhaps I should explain my method. I cut birch ply up to 1/16 and liteply up to 1/8 using a brand new high quality Sheffield steel blade in a Stanley knife holder which is comfortable to grip. I use a nylon cutting board ( household type ) to support the work. Just the tip of the blade is used and first of all a light groove is scored using enough pressure to ensure the blade follows the line and does not deviate to follow the grain. Then further firm cuts are made until the cut mostly penetrates through. Then the work is turned over and the cut is completed from the reverse. A wide straight edge is used where possible. Each cut is made pulling the knife towards oneself with ones body weight over the knife. Only short controlled cuts are made and the workpiece is turned as necessary so that the cut is continually pulling towards oneself in a very controlled manner. The pressure / weight is always right over the blade tip and the angle is kept as near the same as possible - much safer than making long sweeping cuts where the blade can swerve into fingers or body. All this is much quicker to do than to write about.

Just as with a fretsaw safety glasses should really be worn and I suppose a traditional thick leather apron as well any time one uses a knife or scalpel just in case. A tee section metal straight edge is better to protect ones fingers. ( I use various lengths of aluminium tee section, in theory the hard knife metal should wear it unevenly and reduce accuracy but this has not happened so far with occasional use )

I doubt this will change P.M.'s or Steve's techniques but it may help some newcomer try it and decide the best method for himself.

[Martin McIntosh]

A couple of comments which may be of use. 1-To make a mirror image of a single sided wing plan, simply coat the required areas with paraffin to make the plan translucent. By the time you have completed the model it will have evaporated. 2-To cut ply up to 1/32", just use scissors. Above this, use a fret or preferably an electric scroll saw such as made by Dremel or sold by B&Q. Lite ply up to 3mm may be cut with a standard Swan-Morton scalpel, but unless you have the ability to regrow fingers do not try this on birch ply above 1/32"! 3-I now always go for "hairy" mylar hinges glued with super thin cyano. Just a thin slot is required and the installation is very quick and definitely permanent. 4- I have built a few various Caps and intend to build this model, but with much larger ailerons and will try a 600W electric set-up.

[Peter Miller]

I can't work out why you need much larger ailerons...it isn't a fun-fly or 3D model?

[Martin McIntosh]

I want it to more interesting!

[Nick Chudley]

You go for it Martin.  It's going to be a 3D model now alright.  I too have used hairy Mylar with thin CA for hinges with no problem at all (not even extra thin).  Maybe due to being electric we can get away with a lighter and less robust airframe for a given wingspan.

I know a bit about CAP 232, which is 3D, But Maybe CAP 21 is different .. this thread started with a question about dihedral braces ... doesn't that put it into a whole different category?  For 3d performance I've seen just a little dihedral, where the top surface is a straight line from tip to tip.  The dihedral belongs to the bottom surface simply because the outer ribs are thinner.  If you want interesting you don't need any more than that.

Please correct me if I'm wrong - I'm sure you will - but be gentle with me, I'm only a couple of years into this brilliant hobby and I'm still a learner.

Nick

[Martin McIntosh]

Nick, yes, the wing will be flat on top. I intend to use this design because 1) it is the right size for the intended power plant, 2) most Caps fly well, 3) everyone else seems to go for the 232.

The hinges mentioned wll work with most models, but obviously not giants. You must use SUPER THIN cyano.

[Nick Chudley]

Maybe thin CA never failed because I always crashed the plane first.  I'm getting better now though.

My current 3d model is a Stella from a kit by Stevens Aero. Not unlike CAP 232, Edge, Extra and Groove.  I'm not sure I can tell the difference between all those, though I haven't seen them in the flesh. I've survived about 150 flights with it now and I checked the hinges today - no sign of any problems yet and I do make them work hard. AUW is only about 18oz.

[Martin McIntosh]

Nick, I was thinking of models up to 10 lbs!

[Flyerjo]

Hello Peter,

My buddy and I are bilding two Cap21 's at the same time but the U/C in the wing is not a good idea so we made a new U/C just in front off the wing and with the weel on the same place accoording the plan.

We will let you now how it flighs.

Sorry if the Englisch is not perfect.

[Peter Miller]

Why isn't the U/C in the wing a good idea? IT is scale and works well.

[Flyerjo]

Hello Peter,

I agree it is scale but we where thinking about the transport and storing of the wing, it is easyer and it takes less place when you store the wing between others.

That was ower motivation for the U/C in front of the wing.

With kind regards.

Still: Sorry if the Englisch is not perfect.

[Peter Miller]

Hi Jo.

Oh Well, what ever turns you on. I do know the problem myself.

You will like one of my current designs, that does have a fuselage mounted undercarriage in front of the wing. Not sure which mag that will be in yet.

You don't need to apologise for your English, it is excellent.

Hope you like the CAP as much as I do.

[Flyerjo]

Hello Peter,

 Here some news from The Netherlands.

Nice to here that it is oke with my English.

Last tuesday my buddy and I made some planes for the wednesday evenings for the coming winter, the choise fel on two of your plans, the Sonerai from the april 2007 mag and the Miss Lizzy from the september 2005 mag. It is posible that we also make two off each planes.

We like to work in advance when the glue is drying you now.

At the moment we are also working on a Citabria.

PS. Can you tel me wat the meaning was off the plan on the backside off the plan of the Miss Lizzy?

There was a plan off the Millibede by Cyril Carr, but I think it is not complete because I mis the wing on the plan and there was no writing in that mag over this plan, can you look this up for me please?

Thank You verry much.

I will keep you informed ubout ower building off the planes.

With kind regards.

 Jo van Weert

[Peter Miller]

Hi Jo.

I don't keep all the magazines, I just tear out the pages with my plan and put them in a file. For that reason I can't really help  with the Millbede plan.

I will say that getting the whole of Miss Lizzy on one side of a free plan sheet was terrible. I don't know how anyoen could build from that. I wouldn't even try.

 I can supply copies of the original drawings on two AO size sheets for 15 Euros if that would help. that would  cover the cost of copies and postage.

[Jimbo565]

Peter,

I built your Tequila Sunrise way back when and fitted Ivine 46. What a flier.So impressed I scaled it up 72" with Irvine 61 power and it flew just as well.

My Cap 21 got its test flight yesterday and its a dream.Now  have plans scaled up by 20% and this will be the winter project.

The Sonerai flies  just as well so keep them coming,

I'm now busy with second Miss Lizzy for one of the club members. First one went around the club and is still flying well. I did'nt have any problems building from the free plan.

I'm surprised there has'nt been any feedback on test flights for the Sonerai and Cap21. I had an email from a chap in South Africa requesting pics of the Sonerai radio installation which he picked up from Sonerai plans help on the forum. It's good to know that there is international interest.

Regards

Jim Carss 

[Peter Miller]

Hi Jim,

When Tequila Sunrise came out there was a letter from New Zealand from a couple of chaps who built 40 and 60 sized versions, one of then used it as a first low winger.Of course Miss Lizzy is based on Tequila Sunrise.

I am glad that you are having such fun with my designs. I only build models that I want to for my own amusement. There have been a few that unfortunately just did not come up to my expectations over the last couple of years, true scale models. They have not been sent in to any mag.

Yes, the CAP 21 is one of my favourites too, I was flying mine yesterday. What engine do you have in yours and have you tried knife edge yet.

 I will be most interested to hear how the bigger version goes, should be a dream to.

Got a couple more nice designs on the way.