|Nov 25, 2011, 05:21 PM|
Tomboy 48" -continued!
Unfortunately it seems we can't add to the existing thread, so please consider this a continuation of Chris's old thread: [Here]
Work and priorities have got in the way of my own Tomboy but last week I managed to get it all ready to go. I spoke too soon about the 22oz AUW, the Blue Wonder is much, much lighter than a Mills 1.3 !!! I've had to put 5oz of lead in the nose to get it to balance at 50% and thats after emergency measures like hollowing the sheet subfin. All in all, ready to go, it now weighs 28.5 ounces, which is considerably more than I expected.
On a fresh 3S 1000 pack, and on an 8x3.8 SF prop, the Blue Wonder pulls almost 100w at full throttle so its still over 50w/pound and in practise its turned out to be a perfect power match. I managed a full afternoons flying on just 2 charges!
Control is bang-bang rudder & 3-position throttle, and the radio is my own design 2.4g Single Channel Emulation radio, which models exactly the old escapement setup. This particular conversion is an original 1960s RCS Guidance System. The 45-year-old button and switch still work fine, but obviously the electronics are replaced. [More here]
Other than a couple of test glides over the long grass (they dont count, right? ) just to ensure it would descend safely, this is the actual maiden launch - I thought if it all goes badly wrong I'd better have a video to remember it by!
The location is Pontefract Park, our club field is in the centre of the racecourse (horse racing that is) and conditions were dull following a bout of thick fog, with a light southerly. There was no-one else at the field so no cameraman and its all shakey one-handed and tripod shots, sorry.
So thanks for the inspiration lads. I'm very pleased with my Tommy! Despite initial doubts whether it would be big enough, I'd recommend the Blue Wonder for the 48" version, its spot on. The Tomboy cruises nicely with just a very gentle climb at half-throttle which is a measured 55 watts.
It responds very well to rudder without dropping the nose unduly and glides pretty well too. There was a comedy moment when I though I might try for a ROG, when the Tomboy circulated wildly, ignoring rudder corrections, ground-looping for England. Hand launch it is then.
Anyway, enough banter, here we go:
If anyone is interested in the radios, heres my Youtube channel: [PHILG2864's Channel] , loads of S/C & Reeds related stuff there.
Heres my website, more detail there: www.singlechannel.co.uk and an older thread on RCMF (Brit forum) [Here]. The Reeds & Single Channel emulation gear is described there along with other contributions from s/c enthusiasts.
|Nov 26, 2011, 12:13 AM|
I must say I admire your dedication to authenticity in reproducing the "single channel" gear in modern format, although I don't think I'll be copying it any time soon - forty-odd years of flying proportional, starting with GG, since I last flew a bang-bang escapement set-up have made me lazy!!
Re the CG problems, I am not surprised you had to put so much nose ballast in. My 36" electric Tomboy has a BRC 120 watt motor and, despite great attention to keeping the back end light, needed 2 ounces of plumbum up front before it would behave. Pretty much all of the power F/F models I have built for electric R/C have had this problem and required either ballast or extreme solutions like cramming the lipo right up front as in the Spartan. The converted rubber designs, like the Tom Tit, on the other hand are fine with the original nose length and have not needed ballast. The exception amongst the power models is the KK Bantam which was designed for a light engine (Merlin) and, due to the large percentage lifting section tailplane, flies with a very aft CG.
I loved your video, it was nostalgic to see Ponty Park again and brought back memories of flying in the first BARCS Radioglide championships held there, the organisation of which I was involved with. One abiding memory of that weekend is of the hundreds of seagulls feeding on the adjacent dump which would periodically rise up as one in a thermal, being joined each time by a cloud of gliders.
Keep pushing those buttons!!!
PS: also nostalgic to see your Remcon Tx. I built one of those in a brief flirtation with reeds. It never worked properly!!
|Nov 26, 2011, 05:07 AM|
Absolutely beautiful job on the Tomboy as well as the flight !!!! She looks like she handles flawlessly and is graceful as can be expected in the air.
Thanks for sharing!!!!
|Nov 26, 2011, 05:29 AM|
Great work on the Tomboy and especially the SC emulation. What a beautiful mix of old and new: A fifty year old design, updated with the help of state machines and assembly code!
|Nov 26, 2011, 02:05 PM|
I cant take credit for the Tomboy build, my pal John built it in return for me building him a S/C setup.
I do have a little Vic Smeed Poppet which has been 'almost ready' for a while now after 99% of an electric conversion... must finish the motor mount on that & get it flown. Thats the one my cat sat on & broke one of the wings clean in two...
Re the radio, I've made 60 or so Single Channel encoders to date... they're all out there somewhere...
Thanks for the nice comments, I'll tell John!
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