Engine Doctor

Cant remember any timing marks on the one I had . But set it to TDC with rotary valve ports set to equivalent of "valves on the rock" ie; ex just closing inlet just opening and it should be fine. No chance of damaging anything unlike poppet valves that can hit piston if timming is wrong. Start engine and if it runs ok with good idle and revs out ok your spot on. If timming is retarded you will get a super slowe idle with very poor or no pick up. If its too advanced then it will like revving but have lityle or no idle. As I said in earlier post dont use castor based fuels in it. The castor will burn onto the rotary valve causing it to stick .

Can you add large potholes and a have a chair that shakes your teeth out when you hit one 😉

Makes sense,

Hi . Piano wire is not what it used to be and varies greatly . Some are lucky and get proper Piano wire that bends and is springy. There is probably a lot made from Chineseium and its brittle . Once heated to cherry red it often becomes brittle . Chris wolfes post re heating ,bending and re-tempering works on proper piano wire if you can get it but some stuff is just rubbish . Good luck .

Just wondering if the wrinkles are caused by not allowing the tissue to soak long enough ? If its still expanding then wrinkles will appear and as its laid over doculam and the dope will dry quickest preventing the wrinkle from shrinking out ? There surely must be some aficionados on tissue application on here ? Mike Smith, a member of our club has been Free Flight Scale Champ many times see his tips here. He doesnt have section about covering over doculam but does silk over tissue etc and worth a read . His models are museum quality and he just lets them fly free flight !

Hope it goes well Matty.

I have some 38 micron matt laminateing film it looks very similar to the thicker version although it seems more elastic once shrunk. I have not covered a model in it yet just a couple of test frames. The lighter film I bought was only 30cm wide so is limited to small sized models. As you say when its flying no one can tell the difference . As Andy says another coat of thinned dope will remove the bloom provided you choose a day with low humidity. Back when NitroCellulose paint was widely used on cars , those of us without the luxury of a spray booth often had patches of bloom on the finish coat if the weather was cold and humid. The cure was either to use Anti Bloom or Retarder thinners. As that was considerably more expensive the alternative was to take a chance and if it bloomed just leave to dry and give a quick flat with 1200 grit then a wet coat of thinned paint when it was a bit warmer. The up side was that do8ng the final flat and a wet coat gave a superior finish.

If you need to adjust the thrust line then simple shims or washers under the motor mount screws will do the job. Or as Keith says in previous post threaded rod stand off mount give you plenty of adjustment.

Hi David. Just 75 micron matt laminating film NO tissue. Its also iron on like traditional film with its own heat activated adhesive ( be sure to get the Hot type and not the self adhesive type ) . Application is similar but needs tidy tacking as it doesnt shrink quite as much as our covering films. For final shrinking a lot more heat is needed but its VERY hard to burn through. I use covering iron turned right up then a hot air gun (modeling type ) for final shrinking. Overlaps are pretty permanent and wont come apart without heat. I found 2 x 100 meter rolls on ebay for just under £30 enough for a load of models !

John . Its a technique used for some time now especially for scale and vintage models. The tissuue effect is desired on vintage but is not very punture proof and doculam give added punture resistance at little weight penalty. The tissue also takes paint very well. I like the tissue effect on open framed models but preffer to use matt laminating film . Really strong , takes paint and cost pennies compared to our covering films. My 60 inch Elf Bipe cost well under a fiver to cover .

I think they now call it Aileron Camber in the manual . From the description it sound exactly the same as Flaperons ?

Hi Dont make the same /similar mistake I made a few years ago. I had a Flair Leo ARTF kit recommended engine was from memory up to 120 Fs. I thought Id fit one of my YS 140's . Suprise suprise the model has a low swept back UC so the 16 inch prop was out of the question. Ended up fitting a 14 x 14 prop to tame the engine that made for some really interesting landings as it still pulled quite a lot of air at idle . Do check out the ground clearance .

A nice YS 90 FS would power that very nicely with probably more power than a OS 120 fs. Nice looking model / Build

Hi Don yes 500mah were very tough and Nicads. I think Nicads have a better power delivery curve that would slowly drop and you could feel or see the slower servo responce wheras Nihms go go go go then drop voltage hence the higher capicity. Also our radio have changed . In Nicad days it was 27 then 35 meg radio in the UK and radios didnt brown out like 2.4 but would gradually as said give slower servo responce and gradually reduced range. Some of our radio buffs might be able to explain it better ?

As already said around 1500 mah is fine. Dont be tempted to for higher mah bstteries. Anything over 2000 to 2100 mah are more prone to failure from vibration and are not made for higher drain usage.