Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

My need for speed

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Old 12-13-2011, 08:54 PM
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bob62
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Default My need for speed

Poor mans need for speed
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Old 12-14-2011, 06:12 AM
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Jim Oliver
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Default RE: My need for speed

Details??
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Old 12-14-2011, 06:57 AM
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bob62
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Default RE: My need for speed

We have installed a Super Tiger G-21 46 in the plane. Engine was installed using one of the aluminum plates from a Viper kit. we have installed electric retracts from Hobby People. We installed the battery in the air intake for balance reason. We are going to maiden this coming weekend.
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Old 12-14-2011, 06:07 PM
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Crazy4Flight
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Default RE: My need for speed

which P-51 did you start with ?
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Old 12-14-2011, 06:46 PM
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bob62
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Default RE: My need for speed

The Great Planes combat P-51
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Old 12-14-2011, 06:51 PM
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Crazy4Flight
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Default RE: My need for speed

I have one of those on the shelf plus Santa brought me a new JETT sport 50.

do you have a link to the exact gear you installed? (paved runway here)

what mods to the wing for the retracts?
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Old 12-14-2011, 07:02 PM
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Default RE: My need for speed

your pipe is very long for that engine. that engine isnt very strong to begin with.

I have had two of those planes and a few of the other GP combat size planes. the one that always fails is the elevator.

you must make a stronger one. these are on the stock ones with 25-35 size engines and a jett muffler. your adding retracts, a 46 size engine and a full tuned pipe.
all this adds weight which means more stress on the elevator.

It is a cool project but beaware.....
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Old 12-14-2011, 07:22 PM
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Hobby People.comWe used the 5 lb retracts. The wing is not thick enough to install the retract block all the way into wing, so we stripped the wing, added some reinforcement to the ribs and installed a plate of 3/16 ply to that area and installed the retracts to the plate. The major problem is the thickness of the wing.
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Old 12-14-2011, 07:25 PM
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Default RE: My need for speed

We have cut the header back enough that we have the engine turning 13,000 on a 9/7 apc prop, if it goes it goes
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Old 12-15-2011, 10:34 AM
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Default RE: My need for speed

Should do better than 13K on a 9x7 with just the muffler.

The long pipe will act as a governor it determines the RPM target.

You do not have to start cutting - your best best is to keep going up in prop size until the rpm starts to fall off, or the engine starts misbehaving. Then back off one prop size.

Keep an APC 10x7 handy... i think you might be surprised
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Old 12-15-2011, 01:53 PM
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Default RE: My need for speed

can you post pictures of you install?

thansks bob
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Old 12-15-2011, 02:38 PM
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We started with a what we will call a number three header, by that we mean it came out away from the fusealodge quite a bit. We order a number one header and cut it to the length of the original header. On the original we were getting around 12,600 to 12,800. With the new header cut we are getting right at 13,000. You have to understand this engine is old and well worn. We are waiting on a radio return that is being changed to channel 50. We will set up and we will try the 10 props. Thanks for your interest.

Bob
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Old 12-15-2011, 02:55 PM
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Here are the pictures
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Old 12-15-2011, 03:52 PM
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ORIGINAL: bob27s

Should do better than 13K on a 9x7 with just the muffler.

The long pipe will act as a governor it determines the RPM target.

You do not have to start cutting - your best best is to keep going up in prop size until the rpm starts to fall off, or the engine starts misbehaving. Then back off one prop size.

Keep an APC 10x7 handy... i think you might be surprised

Bob is right, should get more rpm with the stock muffler, whats the point of having a tuned pipe if its not used to its potential? Just curious
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Old 12-15-2011, 04:57 PM
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ORIGINAL: bob62

Here are the pictures
Looks like a cool little project. I had a GP combat Spitfire with my old OS25FP, and it was pretty fast (for me) with that. I have a brand new ThunderTiger Pro36 to put in it, but lost radio inexplicably this summer (stupid Spektrum AR500, I think) and smashed it in. Hopin to pick up another this winter if Tower puts em on sale...
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