Primarily for general aviation discussion, but other aviation topics are also welcome.
By Hooligan
FLYER Club Member  FLYER Club Member
#1785580
I was intrigued by the engine he's installing in Scrappy, the Lycoming IO-720; looking at Wikipedia it's still "in production" apparently, yet has only been used in a few production types, PA-24 400, Fletcher FU-24 and Helio H-800 which total around 400 airframes between them. Conversions such as the Excalibur Queenair and various Pawnee Brave iterations seem to be the only other types to use it.

From what I recall of reading about the 400hp Comanche, it was no quicker than a 250 but was a useful load lifter. Sheila Scott used an American registered example for some of her record flights. I think there used to be a British one at Denham, can't recall seeing or hearing it fly! Bet it sounded good!

Anyway, come on Mike, what about the wings? Or are those stubs around the undercarriage legs all you need with such a mighty donk on the front?
#1785584
Although I enjoy watching the way he comes up with genius ideas for his builds, and there is no doubt he is a clever guy with the ability and funds to get things done.

Something I have noticed that frustrates me slightly, his videos give the impression that he comes up with a great idea and 30 minutes later its been designed, built and tested, be it aircraft parts, workshop builds, instrument panels etc.

Obviously if he filmed every second of what he does the videos would be never ending and boring.
#1785591
Hooligan wrote:Anyway, come on Mike, what about the wings? Or are those stubs around the undercarriage legs all you need with such a mighty donk on the front?

The reason there is little about the wings so far is because he wants to design them specifically for the aircraft and is waiting until he has a final exact weight. His target for Scrappy is 2000lbs.

I believe he is doing a live session tonight which shows Scrappy in its up t date state, rather than the video series which is running a little behind.
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By PeteSpencer
FLYER Club Member  FLYER Club Member
#1792291
Interesting instalment:
I found the biographical details of his mate that he rescued from the State Pen a bit over-long, but relieved that Scrappy didn't get singed by the firing.

Also surprised, I guess , by how tiny the rocket was....

Peter
By Hooligan
FLYER Club Member  FLYER Club Member
#1825096
It's general aviation experimental, we can do whatever we want, so why not?"

:lol:

I notice that the Skycraft Skyshark I mentioned on the "Name the Aircraft" thread, which is sitting at Louisville, is missing its barn-door flapped and slatted wings... know anything about that Mr Patey? :lol: :lol:
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By Keveng
#1825116
TheKentishFledgling wrote:https://youtu.be/qpmTWL_Cyug

Mike’s just revealed one of Scrappy’s “secrets”: nitrous oxide, of course 8) :lol:

It is going to be a staggering machine!


General question Ref Nitrous , , would it really be that effective ? was following a thread about its proposed use in a helicopter , my thoughts is that it would be difficult to control the massive toque induced, where as the aircraft could typically handle the torque but would the whole thing not cavitate leading to a lack of traction unless you had a really clever propeller and lets face it that propeller he has is just a beast. i know they used a water methanol mix in the old radial engines.
Thoughts ?
By Hooligan
FLYER Club Member  FLYER Club Member
#1825120
I think some of the Reno racers use Nitrous don't they? They call it "goin' on drugs". Tom Dwelle who used to race Sea Fury "Critical Mass" lost several fingers when something blew on his aircraft while tinkering with the mechanicals - don't know if that was a nitrous system.
By proteus
#1825212
I also think there are a number of guys in the stol competitions who put their motors on the bottle for take off.

I suspect it may be of help doing ridiculously short stuff at altitude. Seeing what greg miller is doing with his relatively stock supercub though, I do hope we see some videos of scrappy going into really interesting places once he's got it built.
#1825225
Nitrous use is a pretty well established and understood technique which like most other modifications is safe when used sensibly. If you just want 10-15% gain and the fuelling system and engine can cope with it, its fine, but it has to be right otherwise you get detonation spikes which is what breaks stuff.

It can be metered in stages to step the kick in the back.

Pateys engine is far from stock, the cylinder head assemblies are custom made from a single billet (each side) as opposed to the original individual cylinder heads. This increases cylinder stability and cooling, all which will help when he squirts a bit of nitro. This was a race built and proven engine before the Scrappy was even started.

The engines you see blow up on nitrous are usually being run right on the ragged edge to win a race, or just not fuelled correctly. You don't just add Nitrous, you add extra fuel at the same time, but the right amount at the right time!.
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