VogelHund

hi im doing some local two pylon racing and i want to move up into a faster division. its a warbird class using wing area in sq inches divided by 1000 to determine maximum displacement. here is the airframe http://www.espritmodel.com/index.asp...OD&ProdID=3678

im going small because this generally seems to be whats winning... any .60 sized airplane seem to get dusted.

my question is i could use a .40 sized engine in this airframe by adding 3 sq inches of area. if so what engine will offer best performance under these rules .


"No engines that were designed primarily for racing will be allowed. Also
excluded are "Sport" versions of Nelson or Jett engines.
1, Engine modifications are not allowed.
2, Mufflers must be OEM supplied.
3, No tuned pipes are permitted.
4, The engine must be fitted with the original OEM supplied carburetor.
D, The maximum 2-cycle engine displacement will be determined by dividing the
wing area expressed in square inches by 1,000. ''

or i could clip a few sq inches and use a .32-.35 sized engine. what do you guys think?
these rules are to reduce cost and speed. i know some guys are using webra engines not sure what everyone is using tho any ideas will be great info. info on where to purchase a webra .32-.40 engine will be great also thx

Flyboy Dave

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http://hobby-zone.com/p_engineslist.php?manufac=rossi

The .40 Rossi comes with a mini-tuned pipe stock !! This is a killer price too.
This would be my bet.....the Rossi will scream.

FBD.

bob27s

My Feedback: (19)

man... my friggin reply timed out....

Webra .28, .32, .33 worth looking at for the "30" size stuff. All are good engine that like to really unwind.

Take a look at the Kyosho P-51, and the Modeltec .25 size P-51 ARFs as well.

Also look at the GP combat series... the corsair is large enough for an OS .32 or Webra .32
http://www.greatplanes.com/airplanes/gpma1470.html

Of note, the Jett .40 engines are .398 displacement. I think most 6.5cc engines are the same size. Actual 6.5cc is .395
In case that comes into play with your P-51 link there

The Thunder Tiger .40 pro, dead stock, stock muffler -- properly broken in, 9x6 prop ----- 16,500 peak ground rpm is easy.
So a good choice for that .40 size.

Rossi .40 with its muffler is good too. Not a bad value. But it is heavy -- so consider that if attempting a small-plane installation.

Also....
If you can dig up a Webra .40 Q-500 engine - circa 1992-1994 --- well worth a look, especially for a smaller 400-450 sq in airframe.
(this is just short of what the Jett SJ-40 was capable of). Engine had an actual displacement just under 6.5 cc (6.3 cc) which made it more technically a .39 cid engine

Engine match-up --- Webra 55 .... GreatPlanes .40 size P-51 ---- 10x7 prop. The engine does not mind a little nitro propped light like that

The OS55 is a possible choice... runs very well on the stock muffler. Prop selection and airframe match would be critical. But for a big-airframe warbird, it might just do the trick.

Btw... if someone can't get a .61 powered bird fast enough on a 610sqin airframe....they are doing something wrong, or using the wrong .61 engine and the wrong prop.

Oh..... thought i would toss this in. Probably would annoy a few folks since the banned the sport-jett engines of all sizes... here is the next best thing...
http://www.westonuk.co.uk/index_021.htm good products, run well.
No, they are not modified webra engines. They only use the webra crankcase casting.

And... the bottom line here...

If you want to race and win ........ PRACTICE!!
Flying smooth, straight and consistant will decrease your lap times far quicker than tinkering to get another 100rpm out of the engine.

Bob

(edit to include image of a Webra .40 Q-500 version - this was the lastest-greatest version with the barrel carb. Comes with the stock, one piece racing muffler. Early versions with the dynamix carb are good too. Needs to turn rpm wise .... 17,500+ )

Mike Connor

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I hate when that happens. I always highlight and copy before hitting the button on a long post.

bob27s

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yeah... i did that this time !!

VogelHund

wow great info and fast reply guys give me a bit to take all that in and i will come up with a few more questions im sure hehe.

and yes flying straight and smooth is the key during two pylon races.... setup seems to be very crucial.

boomerik

Hi

An MVVS .40 Quickie maybe weighs 2.05 oz less then the rossi has less horsepower then the rossi though but revs higher


Grtz Erik

still4given

Seems as though the rules listed above would nix the Rossi, the Webra .40 Q-500, and the MVVS .40 Quickie, since they were designed for racing and all come with a tuned exhaust, not a stock muffler. Just seems that goes against the spirit of the rules. I guess there could be some argument over OEM and stock tuned muffler, but it just seems that trying to bend the rules is usually what ends up ruining a class of racing.

I am intrigued by the espiritmodel P51 you linked to. I have been looking for a plane that size since I fly [link=http://www.rcpro.org/html/rules/warbird_racing/warbird_racing.htm]RCPRO Warbird racing[/link] and the minimum wing area is 400 square inches. A 1/2" spacer between the wing halves would bring that plane's wing up to 400. In our rules you can run an engine from any manufacturer as well as a tuned pipe, but on a 400 sq ft wing you could also use a .80 4 stroke.

I think Bob's suggestion of a Thunder tiger 40Pro and a bunch of practice would put you right whwere you want to be.

Blessings, Terry

Flyboy Dave

My Feedback: (21)

....there is a stock muffler for the Rossi....it is not a racing engine.

FBD.

VogelHund

yes i think the tuned pipes stock or not will be out of the question ... also anything made for racing.
im gonna ask the race director about the rossi with a non tuned pipe.
if not the thundertiger looks good also tho a bit cheap maybe?

i think the .40 size is the way to go....
being i don't even need to add any wing area to run a .40.
if the displacement being a bit smaller than .40 according to the earlier post.
i guess it varies tho i will need to check on that.

the comment on the .60 size plane was interesting also.
if you get the time maybe you could post a quick brain storm on a setup you think might work.
remember they will compete in the same races as the smaller .25 sized planes running .30 -.35 size engines.
bigger size does not mean a different class. i estimate speeds in the low 100 mph range on a 800 ft track.

i run a formula 1 class also with stock os .91 four strokes.
i use the world models midget mustang and the stabilty around a pylon is so much better with a larger airplane.
a bigger setup for a warbird class has always interested me also... theres so many little ones now.
guys see what is usally winning and go with something similar im in that boat now.
nothing i could wish for more than to compete thrid place or better with a larger airplane! .

yes practice makes perfect or actually perfect practice makes perfect.
i usally gotta imagine the pylons there during practice that takes away from my practice quite a bit .
most guys are there to just fly around randomly doing little tricks every now and then hehe
i like to go fast, turn left and build so my practice time is limited at best.

Thx Guys

BirdDog

still4given

Our club finally installed some pylons at our field and leave them up all the time so practicing is much easier. RCPRO uses a two pole, 700' layout with the pylons skewed to the left so that turn one is 200' from the center of the pilot stations. Makes turn two much farther away so that the pylons can be closer to the dead line. Makes for some enjoyable racing.

Don't let the price of the Thunder Tiger 40 fool you, it is the engine of record for Q500. Probably the best bang for buck out there. Keep us posted on how well that P51 does. I am really interested.

Blessings, Terry

still4given

Hi Dave,

How does the Rossi 40 with the stock muffler compare to the TT 40? So far, each guy I've met who runs Rossi engines has had a lot of trouble getting the idle and transition consistent. The TT is a dream in that department.

Thanks

VogelHund

Yes Terry will do!

looks like a nice ARF a bit heavy according to specs but the retracts wont be there.
also might go with a 3 ch setup not sure on that tho.

at the price of the TT .40 will it be wise to purchase 2 or 3 and see which one test better on a bench?
or they pretty consistent from batch to batch?
thats my only concern if thats the case i maybe better off with a rossi or similar priced higher end .40.


funny when rules are implemented to keep cost down in motor sports usually leads to guys willing to spend whatever it takes to go only a bit faster. if the rules were opened up will all be running Jetts or Nelsons and nothing to R&D and go much faster hehe. i guess it does its job tho and i like the speeds were at now.

faster doesn't always mean better racing unfortunately

Thx

BD

Mike Connor

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Don't let the price of the TT Pro engine scare you. Their quality is very good with consistent performance.

Flyboy Dave

My Feedback: (21)

.....I would put my money on the Rossi over the TT.

bob27s

My Feedback: (19)

I agree....

I have set up a number of TT40pro engines for racing.... they have been pretty consistant engine to engine.

There are a few reasons they tended to be on the top of the 424 sport racing list of "gotta have" engines. Good product, and not expensive are primary.

Razor-RCU

My Feedback: (50)

I have never understood folks who have trouble with the Rossi's. They run as well as anything else WHEN SET-UP PROPERLY.

I would also take the Rossi-40 over the TT-40 for performance, although the price-point of the TT's makes them a great value.

bob27s

My Feedback: (19)

Razor has a good point there....

I owned a few very stout Rossi 40 engines. Mine ran great. After racing duty, they served well in sport planes. All on standard fuel - 10%, 15% nitro.. nothing special. Proper break-in was critical. I think on one or two I threw a head shim in just to broaden-up the needle range a little bit when it was hot outside.

Usually their drawback/weak-point has been the muffler. The two-piece black muffler is ok, but unless it is installed/mounted properly (few modelers mount it properly), the system will leak at the o-ring and the engine will not run consistantly. The "long" one-piece muffler works nice (tended to fall apart into two-pieces.. thats another story) but it is low on backpressure. With the big carb up front, you need some decent backpressure and very good fuel tank pressure to get the fuel to the engine. So a very well setup fuel system is very important.

If you run the R-40 with a full pipe, or a jett or ultrathrust muffler --- it really performs well because it ends up with a better pressure balance and the tuned exhaust takes full advantage of the big flow paths and port timing. Plus since they bolt-on, no o-ring leaks, and they tend not to fall apart.

The other issue tends to be glowplugs. The engine needs a hot plug. Rossi R2, R3 and maybe R4. K&B plugs worked ok too. Plug temperature effectively controls ignition timing. Wrong timing, and the engine simply is not going to transition well.

I think the one main thing that might disqualify the Rossi from the original subject here might be the muffler issue.

VogelHund

yes im leaning to the the TT .40 Pro...
or maybe even a smaller higher rpm webra?

hmm maybe i need to post this into the pylon section...
kinda new here did not realize so many categories here with so much info geeezz its massive!
might find what i need to know from some research on the forum. gonna do that when i get the time.

just want to know what will be better pylon performance lower rpm bigger prop?
or higher rpm smaller prop? 2 pylon 800 ft track...

i hope to get this model under the listed flying weight if possible...
will get the kit soon and get weights on the parts and i will know more about that.

i realize there is similar type airplanes that are lighter ...
im interested in this because the fuse is all fiberglass.
straight and true no fuss i want this thing to fly like its on rails!
so I'm willing to sacrifice a bit a speed for handling if i need to.

rmenke

My Feedback: (13)

MC:

Hummmmmmmmm. I don't seem to time out with rare exceptions. Must simply be faster than you guys??? I wish. ENJOY

Mike Connor

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Your airplanes or your typing? Maybe both.

toro_0397

i am planing to build an f20. i have a 55 ax, they have told me that it is not a very good engine for reving up... how can i improve its performance? also i am planning to buy a new engine for speed aplications, i have two options: webra 55 or rossi 53? what muffler should i use on the webra?
thanks

VogelHund

ok ive got the airplane now and also ordered a rossi to from flyboy daves link... one more thing Dave can you tell me where to purchase the non tuned pipe?

oh and if someone could tell me will i be better off with the aluminium retracts that come with the airplane or make its weight as little as possible with some wire gear?

Thx

BD

Flyboy Dave

My Feedback: (21)

.....call Robert at Morris Hobbies and see if he has an old style stock muffler for the 40.

It looks like this:

bob27s

My Feedback: (19)

(morris is pretty much "gone" ... but still worth calling..)