lfinney

My Feedback: (44)

so how many of the euro speed engines are using the needle bearing rod conversions

BiggerDanno

I-Love-Jets

Well the problem is that to date no speed plane is offered commercially that can be powered by high-performance 10 to 15 cc 2-strokers AND that does exceed 180 mph AND that is readily available in the US or CAN. []

In this thread I've named potential candidates who could change this unsatisfying situation (lack of “true“ R/C speed planes in the US) in future by starting kitting such a purpose designed speed plane including carbon fibre props. Design details for that 210 mph+ plane have been summerised in [link=http://www.rcuniverse.com/forum/fb.asp?m=8751461]post #21[/link].


That there's steady demand for “big block“ powered speed planes is shown in Europe by the very successful Speed Cobra and ME-163 kits offered since at least 20 years with big success.


As for spare parts for your PICCO .80 ducted fan engine, the only way to go is searching for NEW OLD STOCK engines or slighty used ones.

Spare parts such like
[ul][*] the disc rotor induction assembly,[*] the front ball bearing housing,[*] the connecting rod,[*] the crankshaft
[/ul]

that will also fit your PICCO .80 RIRE you will find in the following engines as well:
[ul][*] PICCO .65 marine (non EXR version) or DF [*] PICCO .67 marine (non EXR version) or DF
[/ul]

So you could check out these items at the large ...bay for instance:
190305120462
130304933830
260405133601
220409225631



Or just sell your 13 cc PICCO and go the OPS engine route instead being very reliable high-end engines.

All OPS “big block“ ducted fan, speed and marine engines from 10 up to 20 cc are still available NIB. The conversion from marine to aero is simple in case you purchased a marine OPS engine. OPS engines are as powerful as PICCO or ROSSI high performance engines.
Just do a RCU forum search for OPS related topics. I hope everything has been explained in detail.

Last not least the trusty OS .91 VR-DF engine still is a good alternative for the ambitious speedfreak...

BiggerDanno

I only bought this engine because it was a killer price, so not likely to get rid of it get something different. It looks like it has been run a bit, but not much. There are no cross-hatching marks in the liner, but no scoring either.

I'm going to run it on the test stand to see if it may be worn out. What kind of rpm should I expect from a 10 x 10 APC and open exhaust (no pipe)?

BTW, I thank all of you for the time and effort put forth into this thread.
I think I'm going to get a Speed Cobra if I can find one and either put this engine into it or another.

lfinney

My Feedback: (44)

21-22k rpm, find a cold cold plug please.....

RocketRob

My Feedback: (1)

I would think some what lower on a 10x10 with out a pipe to stage.
17-18kmax

I-Love-Jets

Well, although I've written down many engine tuning info already (PLEASE do a forum search for the term OPS) I'd like to remark again:



Running these ducted fan engines without a tuned pipe is not recommended. – Why?


Because they are timed for operating OK with a tuned pipe only. Without a suitable tuned pipe it will neither jump on resonance stage nor will it unload to those high rpm desired (>20K).



Now some suggestions for static ground testing of the PICCO .80 DF:
[ul][*] MACS tuned pipe #1290 or 1190 (the latter leads to highest rpm)[*] pipe length from glow plug to middle of the pipe belly = 30 cm[*] ROSSI R8 glow plug[*] needle setting always on the rich side => big white smoke trail is essential![*] at least 20% of oil – very important[*] take the Zinger 11x10 wood prop (#513) and cut it down to 8“ of diameter[*] don't forget to balance the prop after shortening the diameter[*] that 8x10 wood prop now is your test prop only for engine tuning at the ground! It does simulate in-flight unloading...[*] your flight prop on the other hand should be the same wooden Zinger (#513), but shortened to 9x10. Don't use the APC 10x10 or any other APC sport or pylon prop if it is not a carbon fiber CF copy – the standard APC plastic material is too weak (dangerous) in case of these "big block" speed engines! The Zinger wood props on the other hand are strong enough for this kind of application.[*] If you want better prop efficiency than the above mentioned wooden Zinger 9x10“ just make APC 10x10 carbon fiber copies shortened to 9“ of diameter.
[/ul]

We have to keep the prop diameter always equal or smaller than 9“ because we want to avoid prop tip speeds exceeding mach 0.8! If we do not follow this rule strictly the engine top-end power is instantly eaten up by that huge propeller induced drag...

Due to that 9“ limit of prop diameter the aerodynamic quality of your airframe has to be very good (the less drag the better).

The Speed Cobra for example comes with an airframe design these ducted fan engines already are struggling to cope with efficiently.
Regular sport or pattern ships for that are totally unsuited (too bulky) for these ROSSI, OPS, PICCO, BVM, OS etc ducted fan engines (mainly because of way too thick wing and stab airfoils and the existence of a landing gear). Because of their high overall amount of drag these sport/pattern airframes unfortunately do always require prop diameters larger than 10“ [:@]

But it is impossible to make a ducted fan engine run properly within its defined power band ( = above 20K of rpm) applying prop diameters larger than 10“. []

So the US/CAN “big block“ speed freaks wanting >180 mph top speeds inevitably have to build purpose designed speed planes featuring those special design elements described in this and many other threads before (do a forum search for the term SPEEDCUP please). For instance the European Speed Cup top contenders of the F3S-C and D class do now achieve FAI documented ( = true) speeds of ca. 240 mph. These speeds do result from stringent airframe drag reduction, enabling effective prop diameter reduction (thus rpm increase) plus prop pitch increase. [8D] A common prop size of a 15 cc ducted fan engine powered F3S-D competition speed plane is 7.5x13" for instance.



To conclude:
“Extreme speed“ (in this case defined as true 200 mph+ over the 200 m FAI speed trap in both directions to eliminate the wind factor) can be achieved easily by following just some essential rules. Please don't accept any compromises airframe design-wise and propeller-wise (CF propeller material is mandatory).

Otherwise you will be bitterly disappointed with the speed results when dealing with these "big block" DF engines...

lfinney

My Feedback: (44)

what happens when you run a piped timed engine without a pipe is merely overscavenging, which means much fuel unburned out the exhaust.... it wont hurt the engine at all.....no it wont achieve peak rpm, so what, you are mere running the engine to determine its health. cut a prop down whatever. use your tach, to see what your engine is turning. ops ..80 run about 25-26k with a ducted fan pipe. if they are healthy.

RocketRob

My Feedback: (1)

Hey Danno,

Did you run her up?

BiggerDanno

Not yet. The bearings are notchy and need replacing. I'm still trying to find a sleeve and piston for it (not needed yet, I think...)

BiggerDanno

Wow, in my search for a piston and sleeve for this engine, I ended up with a NIB engine, identical to the one I was looking for parts for on the 'bay.

So, now I gotta find a plane for this engine. Speed Cobra seems to be the concensus, but I'm thinking maybe a 50-60" Delta, maybe a screamin' Demon sized up a bit? It might be more easily obtainable here and cheaper to build too. Looking for 200+ mph.

RVman

Look at the screamin demon .65 build thread on here.

combatpigg

My Feedback: (3)

It's nice to be able to come to the Extreme Speed forum and see a thread that's about Extreme Speed.......[8D]

If I was to "size up" a Demon for a .60-.90 sized motor, I'd think 36-40 inches would be plenty without ending up with a slow poke.

MJD

My Feedback: (1)

NO KIDDING!!!!!!!!!!!!!!!!

Actually, if you use a full 32" CF spar instead one trimmed to 28" as it comes, you get 4" more span and 15% more wing area which seems like enough to me. The fuel bay needs redesign though, and of the 3 big block SD's that are done or soon to be done, two are/will have the engine bay/tank bay mods incorporated to check out. None have the increased wing though, but if the small one flies - which Tom's does - one could safely assume the larger one will. I am not of the opinion that the stock wing with film covering is adequately stiff for such abuse though. I don't think it will frag, it is not a matter of strength; but I think it bends too easily for the flight loads of a 3.65 - 4.25 pound 200 mph aircraft in all but sweeping turnaround manouvers. CF spars are stiff for sure, but unless the skin is well stressed you have only the spar's bending strength on your side. That's why I like my Stits covered wings - the day one of those ever comes apart in the air I'll know someone has flak guns nearby. Fooey on the extra 2-3 ounces, just don't care.

MJD

BiggerDanno

You got a link? I did not find it.

BiggerDanno

Well, I figured if any engine was capable, it would be this PICCO.

RVman

www.MikesRC.us

Edwin68

There is a plane available in Germany, the Nemesis NXT-E. (a downscaling of their big scale Nemesis NXT)

BiggerDanno

Unless you can bury the exhaust inside the fuse, it will probably be slower than the electric.

Edwin68

exhaust inside (macs 1190) no problem, just some organising to do and 2 connected fueltanks.
this one will reach good speeds!!!!!
Everything is being made to fit by the Nemesis designer; this thing will definitely move...........

WestCoastD

wow! I don't even know how you guys can even see this aircraft, especially at that speed. And this is a speed trainer?