Tom Mann

Hi has anyone else come across this remarkable wing section?   http://www.rexresearch.com/klinfogl/klinfogl.htm   As a boy I was given a book by these guys called 'the ultimate paper aeroplane' and made a few from the drawings.  As this article says, it was amazing:   - no stall: just levels off at max height - no tip stall - flies FOR EVER, the glide ratio has to be seen to be believed   The article describes some RC experiments - a tetchy stally model was rendered meek, couldn't induce a spin without serious effort, a prop modified to this section gave more thrust etc etc   So - has anyone had a go, and if not, can someone keen please have a go?  I'm thinking it could be god's gift to beginners in terms of totally forgiving model?  

Thanks all   They were in fact alu pipes - but thanks E.D. for the interesting knowledge - I have brass in another tank!   In the end I bent the long one up as the vent pipe going to silencer.  The shorter ones  simply wouldn't reach high enough in the tank if bent.   The filler pipe is in middle as not bent down - so I'll think to use the feed pipe for draining if necessary (although this makes me think any gunk in the filter will get gobbed bank into the fuel container... mebbe I'll disconnect at the filter to drain.   tom

I have a new bottle tank with thrtee straight tubes, one of which is longer than t'other two.   Is the long one for the "vent" tube, to be bent thru 90 degrees and sit near top of tank?  If so - is this the tube I attach to my exhaust pressure nipple?   If so, the other two'll be feed and fill - but don't need bending - right?   LAstly can I use regular fuel tube for the clunk or do I really need dedicated 'clunk tube'   thanks in advance tom

Paul you beauty!  thanks so much this is clearly the ticket.  tom

I geddit - so I just buy a small capacity battery whose voltage will drop off in the timescale I'm after - or indeed a programmable ESC where I can specify the cutoff voltage if there is such a thing.   good idea boss Still not as user-friendly as a cox with a walnut sized fuel tank though... what with having to recharge or reprogramme ESC for subsequent flights off a single charge. Would have thought there might be a small market for a bespoke 'thing' where you specify the number of seconds of runtime, for free flight toys tom

holy moly that is a beauty Ben - thanks a million for the link, much obliged. Mental note: start playing the lottery!  I must admit though, I agree that the petrols would sound awesome and probably less fussy that glows to match to eachother. Anything in the 60-90" range anyone?

All...and the mighty Tony Nijhuis if he's looking! I'm mad keen to build a nice big P38 lightning (60" or more wingspan) but would want electric to save the faff of tuning two IC's to eachother! Has anyone come across one? Of course if Tony is bored and looking for a new subject...I'm a buyer!! tom

you boys are legends, and a bit mad! Thanks! Rob I hope you're right mate, that does sound SILLY cheap.  OK tonight I'll turn off all the power to the whole house (including her nuclear powered humming sky + box that never bloody turns off, which means she'll miss an episode of hollyenders, HA).  Then I'll charge up the helo pack.  Then I'll boil the kettle to compare.  All this while watching the wheel slowly turn. Boy I know how to have fun.

Hi, I'm lazy.  Has anyone worked out how much hits their electricity bill on a single charge?  My example would be from 3.0 V per cell up to 4.15V per cell on a 4s 3700mah pack.  But any estimates / similar experiments welcome!!  tom 

many thanks y'all for your replies.  I'm going for eagletree it looks pretty slick.  For any UK readers who want to buy: you have to get onto their UK dealer's site https://www.rc-log.co.uk, it worked out at £63 for the logger and whizzy add-on screen to read output.

Aha. This might (pls confirm) explain my bafflement whilst 'improving' on my electric swift chopper.  Whilst footling about spooling up and down alot and trying not to break the ruddy thing I seemed to get reduced flight time out of my lipo.  but yesterday i hovered well non-stop and bejeesis the thing just kepton going.  my concentration went before the pack did. ~What I'm thinking is that all this heat mentioned above is energy after all, and so is 'wasted juice' and that's where my missing flight time went? tom

Hi all I'm looking to build an ultra simple plane with no ESC, just a full power electric run with timed cutoff.  Scouring the web I see lots of nice things that seem to do half of this but then connect to a 'relay' which connects to a leg bone and a hip bone. e.g. http://www.hobbytron.com/CK002.html  Being quite lazy, it'd be nice if someone would sell me a gizmo that I can rig up to my existing circuit of battery+on/off switch+motors (presumably instead of the on off switch) where I could twist a knob to set it to 10 secs or a minute of power depending on size of field...  I don't understand whether it would run off the main power cells or off some aux cell. anyone crossed this bridge already?  tom

On the pusher/puller question, I have a guess.  A pusher setup will drive the prop towards the motor and airframe, so every vibration/pulse will be shoved into the airframe, making it resonate hard. A puller will drive the prop+shaft away from the airframe, with the airframe getting tugged along by its prop shaft. Clearly this is layman's speak and pure fantasy but I think there might be something in it. tom

Jetsome that's a cool idea.  How big was your exit from the fuel proofed wooden box?  Was the power loss related to this obstruction to exhaust? tom

Wattmeters typically go inline between motor and ESC, and display voltage, current draw and power consuption in REAL TIME.  So, for a fixed wing you leave the canopy off and stare at it while you run the motor up. Somehow this loses its appeal when dealing with a 1m diameter main rotor spinning at 2000RPM.  I personally won't be anywhere near the thing to look at it, as I am quite attached to my appendages.  Has anyone seen a product that will store historical data and present a report (average, peak, max/min etc? Come to think of it this would be a touch for fixed wing too because you could get a report based on a real flight (surely more valuable than a ground run).  tom

Wotcha Kiwi My best result was a new motor mount which features a metal plate bolted inbetween backplate and cylinder case, with said plate attached to firewall via three rubbery things.  This limited transmission of vibes to the airframe.  Half the noise comes from the airframe hitting a nice resonant frequency and actually acting as a drum.  Oi Timbo you're everywhere pal.  I've seen things called 'actuators' in full size rattly helis... they 'read' vibrations and actively produce equal and opposite vibrations to cancel out the frequency.  Anyone played with these on a small scale? tom

OK LVC is low voltage cutoff.  I take it that is different to an over-current cuttoff (which may be 'uncontrolled' I guess as in it melts...) or maybe it is the same (vague recollection of volts and amps being inversely proportional)?  Ref dedicated ESC, I don't think it is.  I'm running on an aux receiver pack, but still I would still like a LVC to protect the expensive lipo.  Actually scrub that comment:  £heli > £lipo!!!  Also was concerned that the ESC destructions told me to 'cut a wire' to disable BEC.  Sounds a bit severe....  Shirley there are non-BEC dedicated ESCs?  I'm in the shop tonight, and equipped with this info I will be able to have a grown up conversation!  Thanks again Timbo.  As you might have realised I'll keep asking things till you get bored of answering! Ref Wattmeter... if it involves me getting up close and personal with 1m diameter of main rotor @ 2500RPM , I'll probably give it a miss.  Do you know of a heli-specific solution?  I can always stick this in the heli forum I suppose...I know how you feel about these technological marvels (sometimes I spend 10mins of quality time looking at swashplate linkage go up and down.  It is a thing of beauty.)

Thanks Tims, that was spot on and, timbo, nearly funny .  Don't worry yourself about the size of my chopper too much... I only use it (and the 2 indoor choppers) to sate my stick twiddling needs given that my nearest F/W club is not near and requires knife-edge s-bends on finals.  But hey that's another rant.  I mean who needs flying fields anyway eh?  Much better to buy lots of models and spend quality time jut LOOKING at them.  grr.  anyhoo, I think Timbo's final point about pitch change  is key here.  In the hover I'll be at similar pitch most of the time.  The only time I'd kick the amps up (if I've understood this and other reading) is if it was booted skwards on coarse pitch, and even then it would only be a short burst before the thing went out of sight.  All the same the ESC might cut out on the peak?  I must read the destructions, presumably the thing will say what peak, and peak duration it will put up with b4 throwing toys out of the pram (must practise that autorotate).  I guess an analogy would be a variable pitch prop but few F/W modellers get that clever haha. tom (so nearly in the 'tim' electric club, just one vowel)

Good thread y'all, thanks.  I was sold a complete powertrain for my Century Swift electric, and I trust these guys.  However I noticed that the ESC they gave me is rated: - higher than the battery  'continuous' rating in Amps - lower than the battery 'max bursts' rating in amps - also lower than the middle rating something like 'sustained' rating in Amps Why do I not need an ESC that is rated higher than the max bursts and sustained? Also what is with the '25C' rating on the battery alongside good old amps.  What does the C stand for??  yours stupidly tom

You're brave Dave, there's remarkable interference up there, and also a bylaw enforced occasionally by council sherrifs... Word is it's the HGV CB radios doing us in. also lots of kiddies and dog walkers etc. Mind you I saw a man with an edf delta doing serious pattern work the other day! tom

OK here it is on video. Sitting right on the stall the whole time and almost slow enough!! http://www.youtube.com/watch?v=ntSLZ8w1YHY

Hello web punters Do you know of a flying site in / nr London where you can just go and fly ad-hoc (at risk of less controlled frequency use and all the perks of club membership of course). Personally I'm interested in South/South-east London / top of Kent. I'll kick it off - the old Croydon airport near the top of the A23 / Purley. Quite a scene, fairly well controlled, high availability esp for electric. Thermals off a flat field too! I suspect some people like to keep things secret to avoid overcrowding, but hopefully us liberal web-users can crack the code!

Spot-on - an ultralight biplane! I'll find out the flying speed and post here t

Thanks ever so much Mike and Alistair. Right then. We're stuck with air so ditch that factor. From your excellent explanations we need ultra light aircraft with large wing area and large chord. This fits the description of a nippy little foam number I got for my son recently but still isn't front room material. Biplanes have twice the area but presumably drag and interference between the wings means you don't get double the lift - however you must get more. So a biplane or even a triplane is probably the way to go? Has anyone seeen or attempted a really tiny bi/triplane fitting this admittedly ugly description (a delta biplane???). Really we need about 0.5m/s tops for front-room flying. tom

OK thanks all for responses! Mike - Wing loading is relationship between weight and wing area right? So if 10cm wing, the same wing loading as full size would require very light weight to make the same ratio. I can't believe it would need to fly at min 50mph to stay in the air? I looked at Reynolds number - it seems that you're saying that it is the turbulence of the flow at this small size that disproportionately knackers the lift on a baby model. Apparently there's something else about moment arms that is non linear i.e. it is disproportionately easy to roll a small wingspan, hence the 'twitchyness' of small models (and difficulty in flying in a smooth scale manner). This could be cured a bit with clever avionics, it's just the airspeed issue that seems insurmountable. How are we gonna crack it? More wing area for same weight? Triplanes? Ultra light weight must be the first target shirley. I've seen those fairy-liquid dipped efforts flying indoors at v slow speeds -and then there's the plane that man pedalled across the channel - lots of area, low weight.