Remote Control Planes

[redshift]

The best thing (IMHO) about electrics is that it makes multiengine aircraft so much easier.

And no, it doesnt fit in the TVR either

[Jonathan]

So what electric motor might be best suited for my next project which is a 50-60" span PBY Catalina ? (twin engine if anyone's not familair)

It's going to be ply / balsa airframe with GRP to seal the hull for possible water landings (hand launch) and to make moulds for MK2-3-4-5 etc

Was going to run a pair of .15's but I much much much prefer the ease and clenliness of electric flight. No aerobatics just a scale flyer.

[fflyingdog]

The best thing (IMHO) about electrics is that it makes multiengine aircraft so much easier.

And no, it doesnt fit in the TVR either

Hi Pete

Is that a kit? Is it foam consruction? Kind of fancy one of them .............whats it like to fly?Looks really nice btw

Nick S4s

[MKE40]

So what electric motor might be best suited for my next project which is a 50-60" span PBY Catalina ? (twin engine if anyone's not familair)

It's going to be ply / balsa airframe with GRP to seal the hull for possible water landings (hand launch) and to make moulds for MK2-3-4-5 etc

Was going to run a pair of .15's but I much much much prefer the ease and clenliness of electric flight. No aerobatics just a scale flyer.

Amphibians.

Now you are torkin' Jono.............. Surely the most graceful of all aircraft ?

Schneider trophy class, Catalina, Spruce Goose, Sunderlands . Real Hostesses with seamed stockings ??? The mind Boggles.

Just love those steps........

( Thats on the hull, for you land lubbers !)

Mike

[redshift]

Jon,

for the PBY you need something around 75watts/lb so it depends on what the weight is expected to be.

(Something like 200w would be a reasonable replacement for a 0,15ci motor.)

The biggest problem with twins is what happens when you lose an engine. Normal result is a spiral dive into the ground before you can catch it... With electrics you can run a pair of brushed motors in series and that problem disappears.

As an example, the Lockheed Starliner runs on just 4 x speed400 motors (wired in pairs) 2,33:1 gearing and 8x6 props for around 5lb total weight. (Its also a scratchbuild in balsa as I couldnt even find any plans for this model let alone a kit.)

Edited April 25, 2007 by redshift

[Jonathan]

Mike - I only understood 1/2 of that

The cat is one of my favouritest of aircraft, the Sunderland also used to be moored not far from here at Chatham / Rochester docks before it was sold over seas. There was a cat at Duxford but someone said it had been done in 'Greenpeace' colours now (WTF ?!?)

Pete - thanks for the info. I was very suprised to see the specs on brushless stuff last night when I did some research, electric subs for .60 engines with direct prop to rotor, amazing !!!

MK1 is going to be 58" span, about 1.5kg flying weght to get a rough wing load of about 17oz/sq ft which seems to be a nice balance between dosile trainer and manouverability.

200 watts is spot on actually - I done the calcs earlier and it came to 192 watts.

Good call on the engines, but running them in series wont that cause a larger volt drop across them and make them slower ?

I was more tempted to buy 1x 60 amp speed controller and run them off that in parallel

I saw a guy make a BEAUTIFUL P-38 lightning and the engine splutter on take off causing the plane to slew around, the tip stalled on the slow wing and the thing spiralled into the ground

I was going to go for something like an EMAX 2810/20amp with 1100 rpm/volt and a 7x4 3 blade prop for looks.

Not too fussed on the flyability, I just love building the things - when I build the 80" span one I need to work out how to make the retracts.

[MKE40]

Mike - I only understood 1/2 of that

The cat is one of my favouritest of aircraft, the Sunderland also used to be moored not far from here at Chatham / Rochester docks before it was sold over seas. There was a cat at Duxford but someone said it had been done in 'Greenpeace' colours now (WTF ?!?)

Pete - thanks for the info. I was very suprised to see the specs on brushless stuff last night when I did some research, electric subs for .60 engines with direct prop to rotor, amazing !!!

MK1 is going to be 58" span, about 1.5kg flying weght to get a rough wing load of about 17oz/sq ft which seems to be a nice balance between dosile trainer and manouverability.

200 watts is spot on actually - I done the calcs earlier and it came to 192 watts.

Good call on the engines, but running them in series wont that cause a larger volt drop across them and make them slower ?

I was more tempted to buy 1x 60 amp speed controller and run them off that in parallel

I saw a guy make a BEAUTIFUL P-38 lightning and the engine splutter on take off causing the plane to slew around, the tip stalled on the slow wing and the thing spiralled into the ground

I was going to go for something like an EMAX 2810/20amp with 1100 rpm/volt and a 7x4 3 blade prop for looks.

Not too fussed on the flyability, I just love building the things - when I build the 80" span one I need to work out how to make the retracts.

Jono,

let me explain to a young man about seamed stockings ........................!!!!!!

No forget that . ............................................ Schneider Trophy races held inthe Solent in the thirties were very hotly contested by many technically advanced nations especially those wishing to gain a military advantage in the air. The Italians and Germans were very keen to compete. I wonder why ?

Also in the Solent area in Southampton Water a few years ago the only Cat in Europe made a bad landing and unfortunately killed the mayor of southampton amongst others. I understand the cat involved is now flying again and maybe the Greenpeace cat that has been mentioned.

Actually I think I misinformed you , it was the Princess and Empire flying boats that had those 'Hostesses' Sighhhh !

As far as elegant flight is concerned , the interface between air and water that is bridged by flying boats , floatplanes and amphibians is just so beautiful , so elegant , so intrinsic as to defy description, spesially as I feel a dwunkon evring about tu kreap up on me,

Thank you Mr Carlsberg , for your fine medicinal products !

Mike .

[redshift]

MK1 is going to be 58" span, about 1.5kg flying weght to get a rough wing load of about 17oz/sq ft which seems to be a nice balance between dosile trainer and manouverability.

Did a rough simulation and 'low tech' solution would be:

AUW 1500gm, Wing 58 in span, 435 sq in, 18 oz/sq ft, Stall approx 21mph

Power 2 x Speed 480BB Race, 3:1 gearing, 8x6 props wired in series with 6S 4000mAh LiPoly batteries. 15A max current.

Would give around 20mins flight times.

(With the motors in series it is using a higher voltage in total)

If you want to play with possible set-ups, have a look for a program called 'MotoCalc8'. You should be able to download a free trial version to evaluate. Its not perfect but it is pretty close.

[Jonathan]

Cool, thanks for that !

[bigsi]

well mr bibs has started something here, i have now joined my local model flying club and one of them had a complete trainer plane for sale with engine, servos, all set up ready for just

[Jonathan]

When shall we form the Lotus Esprit Aerobatic Display Team ?

I need to give up work to get on with my hobbies

[mayevora]

Just couldn't resist this pic. Think its called 'taking over your living room' Bet he's got an understanding Mrs. (or more likely no Mrs at all)

Edited May 4, 2007 by mayesprit

[Tentenths]

Hmmm... ironing board for an undercarriage eh?

Loads more equally bonkers large models can be seen on the LMA's site here

Edit - Ian, just realised that's where you found the ironing board Lanc

Edited May 4, 2007 by Tentenths

[mayevora]

I can't work out where the line comes between hobby and obsession. I mean where the hell would you keep this? Don't get me wrong - what a fantastic model but surely if you are going to build one this big, you might a well go the whole hog and try for your pilots licence and get a real plane. Is it the building of them? Is it the flying? Is it the attention to detail? Don't know the answer but why build a 50% replica - you might as well build full scale. You would vertually need a proper runway for this anyway.

Edited May 4, 2007 by mayesprit

[Tentenths]

Suspect it's escapism.

The LMA are holding a 3 day flying display not far from here over the Bank Holiday. As it's en route to the outlaws might well drop in for a quick look round. Not planning to build on that scale myself but, like you, find the whole thing slightly intriguing.

[Bibs]

Where abouts is that James? Might pop along with the kiddies

[Tentenths]

Rougham Airfield, Bury St Edmunds, Suffolk (adjacent to A14, between Cambridge and Ipswich)

Co-organised by the Bury St Edmunds MFC and LMA. Full details here. Public displays on Sat and Sun from 10 until 5 o'c.