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-   -   Four Stroke Speed Planes (https://www.rcuniverse.com/forum/extreme-speed-prop-planes-104/562614-four-stroke-speed-planes.html)

Flyboy Dave 02-16-2003 05:38 PM

Four Stroke Speed Planes
 
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While not extreme....whattsa' matter with some four
stroke racers ?

Here's my entry....a World Models Dago Red Mustang.
It runs an O.S. .90, inverted, with a 12-9 Zinger, on 15%
Powermaster fuel. It's still breakin' in....turning 9,500
on the ground.

With a little more time, and a little more sauce, and a
little more prop.....I hope to get it going about 125.

Rudeboy 02-16-2003 08:13 PM

Four Stroke Speed Planes
 
In the Netherlands there was some talk about a 4-stroke racing class years ago, when the environmentalists started to pop up everywhere, but the idea was abandoned due to lack of general interest...

Though not in the same league as racing 2-strokes, I am convinced very good results can be obtained with 4-strokes... it just takes a different line of thinking.

After all, there are no racing 4-strokes on todays market. I'm sure that a properly tuned 4-stroke can put out almost twice the hp compared to what todays engines are putting out. Just like a racing 2-stroke puts out twice the power of a standard engine.


Dave,

How big and heavy is that Mustang? What would happen if you put on something like a 10-10 APC? Do you really need the thrust of that 12 incher? Maybe the engine would over-rev with a 10-10, but you can always sand down a 11-11...

In the engines forum some guy posted that he had put extra springs on the valves of his 1.20, thus preventing the valves from floating. He claimed a significant power increase because he was able to let the engine rev higher...
Is the rather abrupt drop in power in most 4-stroke hp charts caused by floating valves? I don't know, but it's worth experimenting with...

Flyboy Dave 02-17-2003 04:37 AM

Rudeboy....
 
....I think it is about 58.5 inches. I don't know how heavy
it is....I'd be guessing. It must be a little heavier than the
all balsa ones. It has retracts, and a retract servo....as
well as dual aileron servos, and a large battery. This, and
the .90 size 4-stroke motor makes it heavy.

It has a large spinner....so some proppeler must extend
from it. Most guy's recommend much larger props than I
run....13's, and 14's....forget the 10's, and 11's.....

I heard that there's a bunch of guy's up in No. Cal. that
race these planes....with the .91 4-strokes....sounds like
a good idea to me.... ;)

If I was planning it over again....to race....it would have
a YS .91 in it....(what else).... ;)

Razor-RCU 02-17-2003 05:14 AM

WHo-
 
Whats-his-name has/had a WM P-51 with a St G-90 (?) and he said it was purty fast-

I told Dave I would take a Dago or a Voodoo with a Saito 100 in it!

james

Flyboy Dave 02-17-2003 05:20 AM

Yo, Razor....
 
....I think it was "Cyclic"....

Don't waste the $$$ on the Saito....for a couple more bucks
you can have the YS....no comparison..... :p

Cyclic Hardover 02-17-2003 08:59 PM

Re: WHo-
 

Originally posted by Razor
Whats-his-name has/had a WM P-51 with a St G-90 (?) and he said it was purty fast-

I told Dave I would take a Dago or a Voodoo with a Saito 100 in it!

james


Yeh it "was" a hauler. Christmas was coming so the plane decided to have a battery failure and flew off into the south forty at a 100mph. Engine faired out okay, had to replace the carb. So it has all been turned into a Kyosho Texan which is ready. I took it out yesterday to fool around and will fly it this weekend.

Flyboy Dave 02-17-2003 11:16 PM

Yo, Razor....
 
....check this out...
http://www.centralhobbies.com/Engines/YS91AC.html

viper21 02-18-2003 12:18 AM

Nice Looking Dago Red
 
Nice Looking Dago, I have an original EZ Dago Red that I am installing my YS 61 2 stroke into and am having a custom header made so that I can run the pipe under the wing inline with the fuselage. I hope that its pretty fast. I also just got a really nice fiberglass cowl that I will paint to match the plane. It should be slick.

The racing class for Dagos was for EZ warbirds and they ran 120 fourstrokes in them. This was back when EZ warbirds where able to be bought. The racing was fun to say the least I have been contemplating a 91 fourstroke and that YS sure looks good. I am not sure how fast My Dago will be with a long stroke pipe and custom header on my new YS 61 Long stroke engine. Any ideas?
Viper

PAINLESS 02-18-2003 02:30 AM

Four Stroke Speed Planes
 
I have the Wm Dago Red with a Magnum 91 4-stroke on it. I run a 12x10 prop on 20% ys fuel. It does about 110 (guestimate). It is also heavy at close to 8 lbs with fuel, and lands hot to say the least.

Its a great plane, my only complaint is the landing gear wire, way to flimsy. Bends on anything but a perfect landing.

Check out SWRA pylon racing for some fast 4 stroke action, attended their event in january and had a really good time, looking forward to the next one.

Flyboy Dave 02-18-2003 12:55 PM

Yo, Viper....
 
....the Ys .61 should be pretty good, and faster than
my plane. I run an O.S. .61RF long pipe in a Kaos, and
the "long-strokers" run sweet. For a two stroke engine in
the Mustang....That sounds like a really good choice. I
noticed in an ad the other day, the WM mustangs are now
rated as .46 to .61 engines (2-strokes). With the fat spinner
a 12" prop is about the minimum.

Rudeboy 02-18-2003 01:20 PM

Four Stroke Speed Planes
 
Things must be different for you americans, but I do not consider 20% as a low or moderate nitro content... I have never used anything over 10%... way too pricey over here...

Flyboy Dave 02-18-2003 01:21 PM

Yo, PAINLESS....
 
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....you certainly are right about the soft landing gear
on the WM's....as soon as I get tired of straightening
the stockers, I have a set of the Robart 609 HD's at the
ready.

I don't know what mines weighs....I bought a fish scale
at K-Mart, but it was junk, and I tossed it. I have a
Magnum .91 (four) also, and I love 'em. I think it runs
right on par with the O.S., but the Magnum really came
to life after about 20 tanks run through it.

I notice the RPM's drop when I take the heat off the O.S.
I think it want's more nitro....but it needs more break-in
time, and may be tad rich on the low end. It's kinda like
it's in the middle of the break-in, and the settings are
changing....and it doesn't transition too well. But we'll see.

PAINLESS 02-18-2003 02:11 PM

Four Stroke Speed Planes
 
I'll have to look into those Robarts. My friend has a H9 P51 and has the same problem with the gear. They must all get their wire from the same place.

I just picked up a VQ models p51B, very similar to the Dago but a little lighter and it came with struts, not sure what brand.

I also have a Magnum 80 and it too took about 15 flights to fully seat the ring. Sweet engine.

Flyboy Dave 02-18-2003 02:23 PM

Four Stroke Speed Planes
 
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The Robart's have the thicker wire, and are tempered.
You have to heat it and bend them at the bottom for
the axle....to the correct length, then cut 'em with the
little dremel cut-off wheel. They're twice as strong. ;)

And they come in 90 deg (flat, pattern type), or 85 deg
(dihedral type).... :D

viper21 02-28-2003 02:19 AM

EZ Dago Red
 
Hi Dave, I am just getting ready to build my original EZ Dago Red ARF and I was going to run my new in box YS 61 LS but I dont think the Long stroke is the best engine for it. I also bought an aftermarket fiberglass cowl and I am going to paint it to match the plane. So that YS 91 that you linked above how do you think it would run in my plane? I need to have a custom header made because the engine is inverted to run my YS 61 two stroke and I really dont want to go through the whole hassle of getting it made and then tuning the pipe. I wonder if the YS fourstroke would make as much power as my two stroke? What do you guys think? It would sure be easier to install as I will not need a pipe or special made header :D I am really considering the 91 four stroke instead of the YS 61 which wont produce the RPM's I wanted from a 2 stroke anyway? Ideas please.
Thanks Viper

Flyboy Dave 02-28-2003 02:27 AM

Four Stroke Speed Planes
 
Get the .91 YS four-stroke, and mount it inverted. It will
kick the pants off the .61 2-stroke. The .61 long stroke
will pull a 12-8 Zinger at maybe 12K tops. The .91 4-pop
will pull a 12-10 Zinger at about 12,500.

Dave. :)

viper21 02-28-2003 02:36 AM

Dago Red
 
Well I think that I will buy the YZ 91 and install it into my Dago. It should move pretty well I would think I think I will run an APC 12x10 or even 13x10 on YS 20/20 fuel. Do I need to run a special fuel tank for the YS I will buy the engine this weekend.
Thanks Viper

Flyboy Dave 02-28-2003 02:46 AM

Four Stroke Speed Planes
 
Yes....if your getting it from Central hobbies....ask them
what tank they recommend. I think it's the Hayes tank.
I'm gonna get one too....I have a feeling there going to
discontinue the .91, and come out with a 1.00.
I still can't believe they discontinued the beloved 1.20,
and came out with the 1.40....at a much higher price.... :eek:

viper21 03-02-2003 11:33 PM

EZ Dago Red and Four Stroke
 
Well Guys, I have finally decided upon which engine I will put into my new in box EZ Dago Red. I have two new OS 91 Surpass II's with Pumps that I bought a while back for a twin project but I didnt get the plane. So I am going to put one into my Dago Red and run a 13x10 or even 14x8 to clear that big spinner. I dont know how fast it will be but it should sound nice. I just can justify buying another 91 four stroke when I have these two new ones sitting on the shelf and some others also. So I will see how she flies with the Pumped 91 this is the new black valve cover version. I hope that the engine runs strong, I know it wont be as strong as the YS but if I want to go really fast I will fly one of my jets ;) Standby for pictures as I need to match the paint for my fiberglass cowl and buy a 3.5 inch aluminum P51 spinner.
Viper :cool:

Flyboy Dave 03-03-2003 01:26 AM

viper21....
 
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....one thing's for sure....you're gonna love how the O.S.
fits in the plane. Real good cooling too.... :D

Dave.

viper21 03-03-2003 01:41 AM

Spinner
 
Hi Dave, which size and make spinner is that? I want to buy a new aluminum spinner for my Dago. The fiberglass cowl that I bought will fit a spinner that is about a 1/16th of an inch smaller than a 3.5 inch spinner. So I figure I need a 3.5 P51 aluminum spinner. I see that Central Hobbies has them. Is yours a P51 type Spinner it sure looks nice? I plan to use an onboard glow as well.
Thanks Joe

Flyboy Dave 03-03-2003 02:06 AM

Four Stroke Speed Planes
 
I'm not sure what size that spinner is....it comes with
the World models Dago Red. I just have a remote glow
on mine, not on-board glow. Great engine choice on the
O.S. :D

viper21 03-03-2003 03:31 AM

Dago Red
 
Thanks Dave, I think the Dago will be pretty fast with the pumped 91 on it and I wont need to mess with a tuned pipe and special made header. I will most likely run a 13x10 APC prop on it for starters and see what kind of speed I get. I still need to break in the engine as its still new but I am sure it will move. Stay tuned for pictures.
Viper

Flyboy Dave 03-03-2003 02:47 PM

Four Stroke Speed Planes
 
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A guy showed up at the field with this baby. Another
4-stroke Speed entry. I didn't get to see it fly....I think
it had a .91 O.S. in it....VERY COOL. :D

viper21 03-03-2003 10:33 PM

Corsair
 
Very Cool Corsair Dave. What make was it did you get a chance to find out because it sure looks nice. I am going to put the Dago Red together sometime this week. I need to do a little firewall strengthening with some glass and resin on the inside of the plane. And then I will build it as normal. The biggest thing is finding the correct colors in a paint that I can airbrush on my nice big one piece fiberglass cowl. The one weak point of the EZ P51 is the cowling so I am fixing that right away. Then I will clear Coat the paint with my 2 part auto acrylic gloss clear. I will search the Testors Model master paints for a match. I will post pics when she's done.
Viper


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