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

Twin engined Shrike with OS 25's.

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Old 11-07-2005, 08:38 AM
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vt325xi
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Default Twin engined Shrike with OS 25's.

I just crashed both of my Shrike 10's. One was running an OS 15 LA and the other an OS 25FX. So I ordered two more kits and another OS 25 FX from Tower. I'm planning on making a twin engined Shrike with the 25's running 8 inch props. It will be fast for sure. Here's a quick picture of what I expect it to look like.
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Old 11-08-2005, 11:14 PM
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Default RE: Twin engined Shrike with OS 25's.

Looks nice,however lf its speed your looking for build one of the kits and put a 32 in it. It will be a lot easier to land also.
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Old 01-01-2006, 08:51 PM
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Default RE: Twin engined Shrike with OS 25's.

Ok, as promised, here are some assemby pics to follow as I continue this speed shrike!

To strengthen the wing spar, I used 3 Carbon Fiber arrow shafts from Wal-Mart. And hard wood Spruce for the leading edges. The engines will be matching OS.25FX's. The center line will allow up to a 9 inch prop with 1/2 inch room.
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Old 01-01-2006, 10:28 PM
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Default RE: Twin engined Shrike with OS 25's.

with two 25 I would use 8" props and more pitch

will you be using stock mufflers, MAC's Muffler, tuned pipes or Jettstream mufflers?
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Old 01-03-2006, 12:04 PM
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Default RE: Twin engined Shrike with OS 25's.

Now that is gonna be a fun plane!
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Old 01-03-2006, 06:20 PM
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Default RE: Twin engined Shrike with OS 25's.

I've almost completed the assembly of the fuselage and wings. Now it's time to start cleaning out the engine compartment and shaping the nose. I'm also starting to figure out how to run the servos wiring from one fuselage to the other so that I can have one receiver and one battery pack. I'm still thinking a simple 4 channel should work fine for this setup and I have good luck with the Hitec Feathers. It's got really good range but doesn't like it too much with other close RX on similiar frequencies.

I plan on using the standard OS mufflers on this. I like the simple and rugged design. I've had my MACS pipe fail at the weld one time on another Shrike.

Here are some pictures of the built up airframe. Now comes my favorite part, sanding and shaping the wings and nose! Balsa dust time.

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Old 05-27-2006, 06:59 PM
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Default RE: Twin engined Shrike with OS 25's.

The Twin Shrike is now complete. I got the engines installed this afternoon and fired them up. I do need to spend a lot more time in getting the two engines running the same speeds.

Here are some pictures.
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Old 05-27-2006, 08:08 PM
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Default RE: Twin engined Shrike with OS 25's.

Dude! Look at you! That is awesome!

I cannot wait to hear how everything goes---

Rock-on
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Old 05-28-2006, 05:40 AM
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Default RE: Twin engined Shrike with OS 25's.

Maybe a little disorienting scheme... but it looks powerful anyway
Keep the pix / vids coming !!
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Old 05-28-2006, 09:32 AM
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Default RE: Twin engined Shrike with OS 25's.

Nicely done! For the fastest possible set up, I would put my money on a pair of 7x6 APCs, providing that those .25s can spool up well enough to make this idea work.
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Old 05-28-2006, 10:07 AM
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Default RE: Twin engined Shrike with OS 25's.

and pipe those !!
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Old 05-28-2006, 11:09 AM
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Default RE: Twin engined Shrike with OS 25's.

Wow, that thing is cool. Man you have some skills in building!! Make sure to send us videos of the maiden
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Old 05-28-2006, 11:18 AM
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Default RE: Twin engined Shrike with OS 25's.

I just flew my .40 LA powered Shrike 10 for the first time last weekend. I had an APC 10 x 6 prop on it mostly because I was worried about having plenty of thrust during the hand launch. I had a feeling the pitch wasn't high enough and I was right. When I put the plane in a dive it was running out of prop - the engine was unloading. Some of the guys I was flying with have flown pylon racing in the past and they recommended an APC 9 x 8.5 pylon prop. I would think with two engines you could run similar size props and probably a bit larger. A .25 FX is probably very close in power to my .40 LA
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Old 05-28-2006, 12:42 PM
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Default RE: Twin engined Shrike with OS 25's.

Nope 9x8 even Pylon style is too much to get maximum power out of the 25FX.

8x6 to start then smaller as Combatpigg stated-- The 25's need to turn up the RRRs
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Old 05-28-2006, 02:12 PM
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Default RE: Twin engined Shrike with OS 25's.

Yep, My only experience is with 3 different .25s, OS FSR, Magnum and GMS, all single engine set ups where you have to play the thrust / pitch compromise more in favor of thrust. With this twin engine plane, I think you can count on the collective thrust of two 7" props being more than enough, the limiting factor will be the tune of those FX engines, will they rev up enough to make 18,000 rpm with 7x6 props? If so, then you will have a 100 mph plane there, which isn't too shabby! OS makes C/L venturis for those engines, which would give them a boost, plus they are easy to open up too. I don't know how much benefit you would get putting a full pipe on a non pipe timed engine, plus the added bulk and drag of the system. Drilling out the muffler exits and remove the baffle is easy to do.
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Old 05-28-2006, 03:44 PM
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Default RE: Twin engined Shrike with OS 25's.

SIMPLY "(-WICKED-)" WOW VERY creative !!!!!!!!

EXCELLENT !!!


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Old 05-29-2006, 07:36 PM
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Default RE: Twin engined Shrike with OS 25's.

I stand corrected... So what do you recommend on a .40 LA? Mine definitely sounded like it was done doing work on the downlines.

So on the twin do you think it will have more top end than a single? I can see where the acceleration will benefit but once the engines are topped out do you think the second engine will add much to the top speed once the extra weight and drag are added to the mix?

By the way, I think the covering job should be prety cool. Imagine a red and white streak moving through the air!

Can't wait to hear the flight report.

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Old 05-29-2006, 09:01 PM
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Default RE: Twin engined Shrike with OS 25's.

I've never seen sport .25s in a role where they were very impressive until the NORVEL .25 came out, that sucker rips for the price! I don't know anything about the OS FX series, but I will bet they gave it a conservative carb opening to make it a good all around engine. That's why you can pick up easy rpm in a speed application by using the C/L venturis.
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