Back to Basics

Getting down to the fiddly bits this morning, one thing I tend to forget is to drill the wing bolt positions before fixing the attachment plate. The threaded inserts are a lot easier to fit than standard "wind 'em in or whack 'em" spiky T nuts. One advantage of threaded inserts is that the hex driver holes make it easy to locate the wing fixing screws when attaching the wing. The attachment plate is angled using a slice of TE section as a guide, hopefully this will be parallel to the top surface of the wing and will allow the use of flat nylon washers under the wing screw heads
I looked on the SIG USA website to see if I could get some info on the Kadet. The model I'm currently building isn't available, but the Kadet lives in various sizes in kit form or ARTF. The redesigned Kadet is now the Kadet Senior, and is a bit bigger.I was interested to see that the power requirements are quite modest, so My original thoughts of using an OS FS .52 made me realise that the model would be overpowered. I have an OS FS .30 that I think might be a better choice, and being less powerful, perhaps I can get away with a three channel set-up. The original Kadet was three channel, and although I have the official plan for the aileron conversion, it does look very much like an afterthought.

Looking good Brian, if it is overpowered you can always throttle back, better than being under powered, personally I would see how the C of G works out and then use the biggest engine you can get away with, on the subject of ailerons, if you add them it will give you more control in the wind

I'm with Chris, it will definately have better control authority with ailerons and be nicer to fly, depends if you want to go full retro or not!

Brian wrote: My original thoughts of using an OS FS .52 made me realise that the model would be overpowered. I have an OS FS .30 that I think might be a better choice, and being less powerful, perhaps I can get away with a three channel set-up. The original Kadet was three channel, and although I have the official plan for the aileron conversion, it does look very much like an afterthought.

According to SIG info your FS 30 is below the recommended min power. your 52 is mid range.

re - 2-Stroke .29 - .40 cu. in. (4.8 - 6.5 cc), 4-Stroke .35 - .65 cu. in. (5.7 - 7.4 cc)

Thanks Chris, Jon and Kevin for your comments, the model I'm building is the original 1972 (?) design, it appears to have been updated in 1976 when the aileron mod was incorporated. The present SIG offering closest to the Kadet I'm building is the Kadet Seniorita which is 63" span, the recommended engines are, 2 stroke .15-.25,
4 stroke .21-.35, hence my opting for the OS FS .30. But as you say, the model doesn't have to be flown at full throttle, and there's the option of a finer pitch prop as well. I suppose flying a three channel model is a bit limiting, but this one is very light compared with more modern designs, so perhaps it would be a bit of a handful in windy conditions even with ailerons. At the moment there's no final decision as the firewall hasn't been drilled yet. Thanks for your interest, keep watching this space!

If you accept that it is going to be a fair weather model then low power and rudder only will be fine. But it will be a handful landing a Cashmoor when the wind is blowing from the north because it simply will not respond quick enough when it catches a gust on finals.

Thanks Mike, are you assuming that my reflexes are sharp enough to apply any corrective input to cope with a cross-wind,?

Brian - Progressing well, just to add one more thought, presumably the additional info on fitting ailerons mentions
a reduction in wing dihedral.?

Colin

I wondered about the dihedral Colin, in my opinion a high wing model doesn't look quite right with a straight wing, I think perhaps it would be OK to reduce the dimension from 4" under one wing tip to 2", although there's no mention in the handbook (oops! I've admitted that I've looked at the instructions) the wing construction uses the supplied dihedral braces without any mods mentioned anywhere. However, if I build the wing with the designed dihedral, then the model might be quite forgiving if I doze off during the flight, SIG reckon that the Kadet is "self righting", sounds more like the characteristics of a lifeboat.
This morning I had to forgo the delights of the building board in order to brush up on various technical matters. Bernoulli and Coanda played a big part, pressure drop versus air speed,and the magic formula which involves "slugs per second squared". Today's foray was in pneumatics, no lift, thrust, drag or CofG was damaged during the procedure. Having demonstrated my ability to get up off my a**e and drive the Dyson, I must now use my Covid-19 mask when I empty the container.
As they said (and never got away with it) " A woman's work is never done.....Properly".
During my coffee break this morning, I decided to have a look at the plan for the Curare. I've had it for a few years and it was in its original envelope, which seemed curiously plump. No wonder! There tucked in with the huge plan for Curare was an older plan for Mike Birch's Moonglow VI, and the build instructions. I couldn't help thinking that it would be nice to have an even older F3A than Curare. However, I really must get on with the Kadet first......I must......mustn't I?

Brian! What do you mean a high wing model without dihedral looks wrong?!!!
Please, treat yourself to a mouthwash! Don't you remember the beauty, grace, unsurpassed flying characteristics of probably one of the most popular models ever designed and flown?!!! None other than of course the incredible, unsurpassed WOT4!!!
Really?