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Old Nov 27, 2012, 09:46 AM
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Harry D's Avatar
Canada, AB, Edmonton
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Quote:
Originally Posted by Sundancer View Post
Maybe some little inaccuracy has crept into the CAD plan here when re-drawing from my original
George, you got me curious so I checked on my copy of the plan. It's more than a "little" inaccuracy.

On the plan view, the stab chord from the leading edge to the hinge line is 4.06 inches. The corresponding dimension on the fuselage side view is 3.79 inches. That's a big difference.

This sort of thing just shouldn't happen, particularly with CAD. I've seen similar errors on other Q&EFI plans. They really do need to smarten up!

As a regular contributor, you may care to mention that to them. This kind of thing makes everybody look bad and causes much frustration to builders.
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Old Nov 27, 2012, 10:22 AM
I like real wooden aeroplanes!
Sundancer's Avatar
South-west France
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I couldn't agree more Harry; however, I have to take part of the blame here as I did have a PDF of the CAD plan to check, and in fact found and had corrected quite a number of errors - but I missed that one. I took the trouble to tile print the plan out and checked a lot of dimensions, like rib lengths vs wing plan etc., but, as I say that was one I missed. I don't have my original "proper" plan so I can't say with absolute certainty that it wasn't my error, although I have just checked my pencil "building plan" from which the "proper" one was drawn, and it is right on that.

This can be quite a problem as when one is going from a "building plan" to a "proper" hand drawn one, then someone else is doing a CAD version of this there is rather too much potential for errors to creep in, and some of them are almost certain to be missed in the checking procedure. It's like the old joke about the message being passed along the trenches starting out as "Send reinforcements we are going to advance" ending up back at headquarters as "Send three and fourpence we are going to a dance"!! For this reason, when I built the double size Mercury Mars, I went to the trouble of drawing the "proper" plan which subsequently went off to the magazine right from the start, and built the model from this. Fortunately it didn't need any significant changes after test flying!

Mind you, given that almost all the kit plans (and a lot of the magazine ones) from the vintage era were inaccurate to some extent, some of them wildly, I suppose we don't do too badly.

Fortunately this one on the Tom Tit is a pretty easy fix.
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Old Nov 27, 2012, 11:48 AM
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Harry D's Avatar
Canada, AB, Edmonton
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George, please don't misunderstand me - I wasn't directing any criticism at you. It is Q&EFI that needs to get their act together.

Even if your original submission had some errors - and from what I've seen of your work I'd be surprised if it did - it's the job of their CAD operators and checkers to catch those and make sure their drawing is consistent and accurate.

I've been in the engineering business all my life, and have been involved with CAD for both professional and personal purposes for over 25 years. CAD makes it very easy to avoid errors such as this one, and any half-decent CAD operator routinely uses standard, easily-implemented procedures to cross-check different views to make sure they're at least consistent.

If this were someone doing it just for fun, all could be easily forgiven. But Traplet is a major publishing company, marketing its publications and plans internationally, and it's not unreasonable to expect an appropriate level of care would be taken to ensure that the final product is "fit for purpose".

And if it were an isolated incident, I probably wouldn't have even commented about it here. But I've seen it on other Q&EFI plans too. As but one example, the last plan of theirs that I built from - the Martian Spaceship - contained a similar error to this one but was even worse (a discrepancy of over half an inch between views).

IMO, this sort of thing is just not acceptable. But I realize it's only a hobby and that I may well be over-reacting. So I've probably said too much already, and will say no more.

Except that if I were Q&EFI management, I would be having a very serious talk to some of my staff.



ps: Looking forward to receiving my December issue and having a look at your Mamba plan.
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Old Nov 28, 2012, 06:34 PM
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Canada, ON, Hamilton
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Colibriguitars, nice build. The Tomtit is on my “to-do” or bucket list. I
did get the same plans this year, so that’s a step in the right direction. For this model I wouldn’t worry too much about a small error on the plans as long as everything fits together in the end. My Lancer 72 has a 75 inch wing! Nice to see another “canuck” (Harry) interested in the same model.
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Old Nov 28, 2012, 07:05 PM
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Hi John, i love the FROG models, but this is one i did not build as FF, so what better than this. and as a plus, designed by Sundancer. itīs a great model. hope to see your model soon!
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Old Nov 28, 2012, 11:31 PM
So I'M meant to be in control?
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Ilkley, West Yorkshire, UK
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I'm not sure how many times I can say 'nice work' about your builds, cg........but nice work!!!!
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Old Nov 28, 2012, 11:41 PM
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Thanks a lot Coronel!!
now iīm thinking about covering and colors.... not to good to take a choice. Here in Mexico is not easy to find a lot of colors of tissue. i will try to get some information to paint tissue.

I was thinking on just clear microlite, but have some imperfections and had to use filler. so you can see white spots on structure.
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Old Nov 28, 2012, 11:42 PM
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Does anybody know some about paint tissue with Humbrol enemel? Maybe Black/Gold
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Old Nov 29, 2012, 12:22 AM
I like real wooden aeroplanes!
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South-west France
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CG; I wouldn't recommend painting the wings if you can avoid it, especially with enamels. They tend to be heavy and also to make tissue brittle. You could get good tissue from www.freeflightsupplies.co.uk, he mails world-wide and tissue is not heavy. Paint on the sheet fuselage would be OK. Lightweight film would be OK for the wings and tail.

Great progress, glad everything fitted on the wings and sorry about the little problem with the tail!
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Old Nov 30, 2012, 01:54 AM
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Hi George, iīm still have time to decide the covering, but maybe just good time to the BritKit... what you think?
i been looking your models, and read about your S.E.5a but did not find a picture...
you know i donīt have much experience in RC, but what can you tell me about flying a biplane...
Have a nice weekend
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Old Nov 30, 2012, 02:55 AM
I like real wooden aeroplanes!
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Hi Rodrigo

Plenty of time to finish your Tom Tit by 31/12/12 - at the speed you build!

Biplanes fly no differently from monoplanes, except that as they generally have more drag they tend to be steeper and slower on the landing approach, which actually makes it easier to land them well. The Tom Tit is particularly good in this, and in fact I think it is the easiest model to fly that I have.

My SE5A is an indoor model I built about 15 years ago, at the time when very light electric power systems were quite tricky and expensive, it was originally powered by a tiny brushed coreless geared motor and 8 tiny 50 Mah nicads. It is an all foam model, built from hot wire cut white foam and is now equipped with an up-to-date micro outrunner and 2S 300 lipo, it originally weighed 120 grams but is now a bit heavier at 135 grams. However, it is still a lovely flier, I have no indoor flying site here but fly it on calm evenings and mornings in my garden. Here are a couple of photos, it is rather battered now after accumulating many airborne hours. When I obtained the foam parts for the original from Dave Ridgeway who designed it, I also got a second set which I still have, so I will build a new one one day, the building is quite quick, but the finishing with an airbrush to simulate the built-up structure is tricky and time consuming!

This is the third SE5A I have had, the first one was a control-line model and the second a diesel powered free-flighter, and like the current one the first two were really good flyers, very stable and easy. It is generally considered to be one of the best subjects for a scale biplane, and one day I plan to build a big one - 50 or 60 inch span for electric R/C. If you would like to build one there is an excellent plan by Doug McHard for a diesel F/F one (that was the plan I used for my F/F model) about 30" span which would convert into a lovely electric R/C, also a small rubber powered ones by Frog and Keil Kraft and a 40 inch power version by Keil Kraft.
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Old Nov 30, 2012, 11:46 AM
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Hi George, i have a 16g brushless arround, with 300 g of trust, so iīm thinking about a SEa5 or Fokker D7 for this, maybe a 27-30 " wingspan, i really preffer the fokker, but, if the SEA5 flies better... iīm just thinking, i need to finish my Tomtit!
Hope HobbyKing donīt take to long to arrive, waiting for Motor and ESC.
lets see.
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Old Nov 30, 2012, 01:33 PM
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Given the choice between the SE5A and Fokker DVII I would definitely go for the SE5A, if built to exact scale it is a much more stable model than the DVII would be. Really with a DVII you need ailerons so that you can build it with scale dihedral (that is; not very much!!), it would probably not turn too well as a rudder/elevator model, whereas the SE, with scale dihedral, handles beautifully in this form. Probably better for you at this stage to stick to a rudder/elevator scale model, you really need to do some flying with an aileron equipped sport (non-scale) model before tackling an aileron scale model like the DVII. As you probably want to stick to models around 40 inch span or less to suit your flying site, something like a Junior Falcon fitted with ailerons would be a good next step, the flying technique is different from rudder/elevator models such as your Tomboy and Redwing or even the Tom Tit, and needs learning with a stable model. But you will be a lot more able to tackle something like this after some flying time with the Tom Tit.
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