August Edition CAP 21 Plans

[Howard Heffer]

Oh, and the thread so far has been awesome! V helpful chaps!

[Peter Miller]

I have to go out guys but will try to anserr your questions and comments later this morning

[PAUL FOX]

It's great to see Peter writing personally about the queries. Who could ask for more than direct communication with the designer himself?

Any news of where we can soon obtain plans for your model of the Sportavia-Putzer Fournier RF7, Peter?

[Peter Miller]

Hi Folks, this has been an amazing thread for various reasons. I see that there are all sorts of things that need explanation and comment.

Right, let's start off with the comment that my plans are notorious for errors. I find this interesting because of the system that I use. I draw the model full size on AO paper, then I trace it and have two copies printed off. I build from one and when I find errors they are corrected on the other sheet which is then as accurate as possible. This is the one that is sent in to the magazine. The plan is then squeezed down to from 2 AO sheets to two A1 sheets. I cannot say what happens between leaving me and being printed.

More on this as we progress.

U/C plate. Yes, it goes right across. It is built into the first wing to be built and then that wing is propped up and the other wing is built onto it. This is described in the instructions.

NOTE, R-1 of the second wing is not fitted until the wings are being joined. This is clearly mentioned in the instructions and explains why there is no rib angle template. I know that reading and understanding instructions is a revolutionary concept but try it!

Aileron and other hinges. I leave that to the builders choice. I use Great Planes Small Pivot Point Hinges. I like these because the have a metal hinge pin even in the small size unlike Robart. I only need two in each elevator and three on the rudder. If you want to add more go ahead, add a dozen if it makes you happy. In passing I also use SLEC Neata Horns.

Rock hard balsa is adequate for the spars, spruce is over kill. I get my balsa from SLEC. The old Balsacraft. Very cheap, superb quality and they send exactly the grades that you ask for. Phone 01953 885279. Very fast service too.

On my original plan R-2 HAS GOT wider notches for the dihedral brace. For some reason the plan has left these out.


I have tried to insert a drawing of the aileron control. I now put it on every plan.

On MY plan I just showed the servo locations, I didn't include the servo bearers. Yes they are on the wrong side of the servo mounting lugs. NOT MY FAULT again.

The CAP is for experienced fliers but isn't tricky to fly.

What worries me is that the next plan scheduled for RCM&E is very complex Oh Dear! what is going to happen then!!!???

Can I go and do some building now, please?

[Peter Miller]

Sorry the drawing of the servo didn't copy. It is my standard system with pushrod to the bellcranks in the wing.

Deatils of where to get the lettering and the canopy etc in the August feed back thread.

The Fournier RF-7 plan is in (will be in) the September issue of RC Model World. There should be a canopy available and also a CD of photos of the full size including lots of detail.

[PAUL FOX]

The errors that I have mentioned in another designer's plans could well, like those attributed to Peter Miller himself, have been introduced at the printing issues. As Peter himself says, he built a flying prototype, so he's not likely to put out a plan of a model that won't fly.

The publishers really ought to add into the process a final check by the designer. After all, not everyone has the internet, and therefore won't necessarily know what the designer has to say post-publication. As established earlier, plans need to be right(regardless of whether they are "free plans"); otherwise, they will probably get built only by those who could have designed the model from scratch.

One thing that comes clearly out of this is that one should be very careful before issuing blanket condemnations of a person's work (... notorious for errors..., etc.) Not only are they unfair; they may well be proved wrong, as in this case.

The Peter Millers of this world are becoming much thinner on the ground, we non-designers who models to build should cherish and encourage them.

[Peter Miller]

Aviation Modeller International do send out plans for proof checking but unless one builds another model from those plans one can't be sure that the shapes are accurate. Usually they say it is coming out this issue please check now.

Personally I have always adopted the attitude at work and in modelling and life in general, if I am wrong I will put my hand up and say "Sorry, Guilty" but will argue until hell freezes over if I am in the right.

Yes, sometimes I do make mistakes or miss something and am happy to correct it.

I only design models that I want to build and fly, it=f they don't fly or don't fly well enough I won't send them in to a magazine. I actually had three last your, two experimental scale models which failed dismally and a very nice scale model that just wasn't nice to fly and eventually, after modifications crashed.
Those only saw the light of day as photos showing that not all models fly well if at all.

[Shaun K]

As a newbie to RC flying I have recently finished building my first plan-built model from Peter Miller's Miss Lizzy plan of September 2005 RCM&E.

It was a pleasure to build and has resulted in a plane that not only looks great but flies beautifully too! The only fault I could find in the plans was the marked positions of the rudder and elevater pushrods in the formers - by no means a show-stopper!

Don't be too harsh on folks like Peter or the flow of free plans just might stop one day. We're all in this hobby for fun, not for life-dependent accuracy. Aren't we... That's right, now repeat out loud "We're all in this for fun".

If you want scale accuracy, buy original plans and scale them. If you want something fun to build and fly then appreciate the freebies and be prepared to apply some neurons to ironing out the odd bug here and there.

Peter Miller - Keep up the good work. I'm now looking forward to tackling the Sonerai plan you put together.

[Nick Chudley]

Quite right, Shaun. I'm with you on this. Some famous cookery writer said: "life is too short to stuff a mushroom." It's nice to build things right and very satisfying to fly the results of your own work. But it's too easy to be so precious about the build that we spoil the fun of flying. Model building is something we do on our own. Flying we do with our friends.

We're all in this for fun, let's get out there!

That said, this thread has been really helpful with several useful tips. A special thanks to all those who keep coming up with interesting new plans and projects. We need you.

[Peter Miller]

Thanks for your comments lads. Yes we do it for fun but I agree that poor plans take a lot of that fun away. I do try my best but sometimes things are not perfect.
I also take notice of comments. Recently someone commented that I did not show the throttle run. I have started doing that now.
Someone else asked if I could include a photo of myself with the model to give a better idea of size. I did with the CAP 21 but they didn't use the picture.
On Miss Lizzy,I try to plot the holes on the formers after drawing to location of the snake runs. For some reason they are not always as perfect as I would like. Must try harder.
There is one other thing. Designing models isn't really that hard, most of it is rule to thumb or TLAR (that looks about right.) Why not give it a try. You never know, you could sell the plans, there is alwasy a demand for them.

[Mike Rolls]

Peter
Not a criticism - just a query. I am intrigued that you use bellcranks to drive your ailerons. I prefer to use two servos with inset ailerons, and with strip ailerions either two servos or torque rods. What do you see as the advantages of bellcranks?
Mike

[Peter Miller]

There are probably no real advantages to using bellcranks. With modern mini servos there is no weight advantage. I can even see there would be some simplification fo the structure in the centre section if two servos are used.
I used to use two servos in my .40 powered models. I suppose it is just the way I like to do things but perhaps I will change with the next design.
I still use bellcranks (or two servos) with strip ailerons because I like the horn in the midle of the aileron. This is for two reasons. One is that a soft strip aileron can twist and so you get less effect out at the tip where it is needed and ,
Two, I never like the horns sticking up in the fuselage, if the wing gets knocked off those horns can smash through the side of the fuselage doing a lot more damage.

[Steve biplane]

Peter,
Perhaps it is worth resurrecting the old Aeromodelling Plans star system for indicating the level of experience the builder is expected to possess. I think these were :-

* Beginner, plan self explanatory.
** Some experience (has already built a couple of * plans) so, for instance, only needs hinge positions indicating because builder knows how to fit a hinge.
*** Experienced builder, expected to sort out details for him/herself.
**** Expert builder,

I think the CAP 21 plan would be in the ** category.

Steve

[Peter Miller]

I agree entirely. Most of my plans are aimed at established builders.
I do tend to send in lots of construction pictures but they don't get used.

[Mike Rolls]

Peter
Good point about the vulnerability of the central horns with a two piece model. Come to think of it, Ive only used a central servo in recent years with small one piece models.
Mike

[Nick Chudley]

Peter
As a ** builder I would say that a picture speaks a thousand words. It's a shame they don't publish the ones you send in. But build threads on the web are always fascinating and extremely helpful.

A question about servos and linkages... 2 aileron servos, situated in the wings seems favorite to me, provided you can keep the servo leads away from anything that might be glitchy. This means, at least with my Tx, that I can use "flaperons" to make the landings a bit slower and add to the interest of flying. The question is: what's wrong with linking these to the control horns with a single, short piece of 20 or 22swg wire with a z bend at each end? I know that doesn't give any adjustment and it's important to get the angles and centre points right. But with care it's not too difficult to get the bends in the right places, then make fine adjustments with the transmitter settings. It's cheap enough to throw the wire away and start again if not satisfied. I've seen a z-bending tool advertised somewhere for a few pounds but I haven't had a chance to try it out yet.

Most of my models weigh 2lbs or less and anyway it's possible to stiffen these wires with a piece of c.f. rod or dowel fixed with thread and cyano. For elevator and rudder, I like to keep the servos close to their surfaces and, in any case, I have used snake tubing with thin wires successfully.

What has given me disastrous results is trying to make the control rods adjustable with heat shrink tubing and thin ca glue. I once wrecked a plane by using plastic clevices, which I was not careful to align correctly. The little pin snapped off instead of controlling the elevator horn! z-bends leave nothing to come undone, or twist, no sloppiness and you can look at them easily to check them.

What do you think?

Nick

[Mike Rolls]

Nick
Never use plastic clevises on anyhting other than small, light, slow models. They can work, and doubtless there are folk who have used them in higher powered installations and got away with it - but your own experience shows what can happen.
20 or 22 swg - well OK for models like the GWS park fliers, but again nothing bigger/faster/heavier for peace of mind.
Yes, Z bends at each end can work fine - but personally I find them a righ apin inmost instances - for a start - how do you install them? Once the horn and servo are in position you have to take the servo arm off.
HTH
Mike

[Peter Miller]

As far as I am concerend non adjustable links are just not on. I use 2mm threaded rods, i.e. about an inch of thread on the end of a rod, with metal quicklinks. I prefer British quicklinks, they have a stronger springyness. American ones tend to be softer and e=need keepers.
Trust me, if you can't adjust something...you will need to.
The Z bend pliers work well on the softer rods but not too well on 16SWG piano wire.
If you want to go the solid wire way make them in two parts and bind and solder them, heatshrink and CA sounds rather "Micky Mouse" to me. We used to do that with big control line stunters and the solder never failed.

[Nick Chudley]

As I say, most of my models are less than 2 lbs, all electric. Stevens Aero make really good CNC kits and I've had a lot of fun with them, learning all the various loops, rolls, stalls, knife edge etc without ever having to change the length of a control rod after completing the model. Yes, installing them the way I do requires: 1) centre the servo and align the control surface with something temporary to hold it in place. 2) put the first z bend into the control horn and then lay the wire next to the servo arm to make the first bend of the other z; with a bit of practice it's not too difficult to get that more or less spot on. 3) make the second bend. 4) remove the servo arm, fit the wire into it and replace it. It's not the end of the world if you have to take it off and start again after a few test flights, but I've never found that necessary.

My biggest model is the one in the picture here. It's a Catalina from plans by Ivan Pettigrew, a.u.w. just under 4lbs. Very stately and gentle in flight so I got away with the above technique. Next project is a Mosquito from the same stable. That weighs almost as much and is miles more lively, with 5-600 watts total power, so I'll follow your advice, use 2 parts of heavier grade wire, then bind it with copper and solder it.

Good plan - Thanks

Nick

[Peter Miller]

I keep looking at the Catalina. Two of us built the old APS control line version many years ago, the wing was horribly inaccuarte but they flew well. The snag with the Cat is that the nacelles are so small. They are ideal for electric motors though.

[Mike Rolls]

You'll be oconverted yet, Peter!
Mike :-)

[Nick Chudley]

my Catalina is powered by 2 little outrunners from Galaxy models ..JP 2832/22 22T, with 9 x 4.7 APC slowfly props, direct drive. They weigh 57 gms each and draw about 160 watts each with 80% efficiency. There's plenty of room for them and I use a li-po 3200 maHr 3S1P battery. This gives me enough power to take off on the hull from grass with the help of a bit of head wind. No fussing with fuel and cleaning up afterwards, no flight box full of goodies. She cruises gently and gracefully around the sky for about 15 minutes before I start to think I'd better bring her in. I think I could get some considerably cheaper motors now from BRC models. Those ones were £32 each. I've just bought some 3 blade props which look much more realistic. Havent had a chance to test them yet.

Nick :-)

[kdc]

I completely accept that the errors occur during re-drawing by the magazine people and are not Peter’s fault, but nevertheless it is his name on the plan.

Frequently the errors are in the ply formers which are cut early in the construction and cannot be modified in the middle of construction. For example, the RCMW Lil Mustang former F5 is about 5mm wider one side of the centre line than the other, and an experienced modeller might assume that the right side is the correct shape but what is the correct overall width? Much the same with F1. Similarly with F4, but surely the recess is too narrow? One can only guess what the overall fus width is at each former as there is no plan view.. A lovely looking plane but significant errors which I have not seen corrected. ( Peter, why not scale this design up to about 55inches and correct the errors? )

Firedrake. F1, F2,F3 and F5 widths do not seem to quite tie up with the plan view.

Volksplane. Some problem with the wing ribs if I remember correctly from when I built it twenty years ago.

Jolene. The plan published in the mag ( reduced size ) shows straight wing tips but the photos show rounded tips with inset ailerons. Maybe if one pays for a fullsize plan the tips are shown!

However the Cap21 does seem to be mostly quite accurate as does the RCMW Turbulent from many years ago.

Maybe my wording was quite harsh but I think it was fair comment which would help a newish modeller and persuade him to study the plan first. Really the point is that magazines do not normally publish any corrections to errors in their plans. Anyway I am glad Peter has taken it in the right spirit. Nobody seems to have commented that Peter Miller is possibly the most prolific published model aircraft designer anywhere.. Surely he has overtaken DB by now..

[Peter Miller]

Once again I say. I build from one set of plans and send in the second print. I do correct any errors that I find.
Yes, just looked at Jolene plan. I didn't get that one to proof. They obviously chopped the wips off to make it fit the paper and din't put them anywhere else.
The worst example was Bootlace. The ribs bore no ressemblance to the originals and I emailed correct sets to several people.
Looking at the reduced scale drawing of li'l Mustang, F-6 looks completely distorted. It wasn't when I built it. The tops of the formers were plotted on my computer program.
I think one of the classic examples was Toot Sweet. People complained that the formers were tapered. They were because they were set at an angle and had to be. Also the plan did not show the plan view of the fuselage, (so few do) and people got mixed up because they didn't realise that the snakes crossed over.
My current score of plans and thre views including plans published in two magazzines and three vinate designs ressurected and with R/C added is 118.
The difference between me and DB is that with very few exceptions I build all my own designs. DB farms out quite a lot of his.

[PAUL FOX]

I think that we all understand your position, Peter, and that it is clear that we all value your work.

It must be frustrating, to say the least, for a designer to hone a model to perfection only to find that the printers put out something useless -which must be the case with a lot of the examples cited by Peter Miller.

If there is to be any point in publishing plans, whether free or otherwise, then the input of the publishers is needed on this thread, to the effect that things will change for the better.