Author Topic: speed limit combat engines (Read 3878 times)

ChrisSarnowski · « **on:** October 04, 2008, 06:41:06 PM »

Anyone try the Evolution 36 for speed limit combat? Also wondering how that new
OS 35 AX is, anyone try it yet?

I'm currently running a square head Magnum 32 xls and a Thunder Tiger pro 36.

I like the Magnum but it doesn't like to restart hot. The TT is better in that respect
but dies on outsides unless I run it rather lean. I'm going to try a hotter plug (OS A3)
tomorrow and see how it goes.

-Chris

Just One-eye · « **Reply #1 on:** October 05, 2008, 03:14:03 AM »

Personally, I consider 35s, 36s, and 40s to be too big and too heavy. If you are using the odd 72 mph rules, the 32SX is lighter than most of the competition, and overweight is a serious disadvantage. I've flown fullsize Arrowplane Fast designs with various 25s, and a couple of 28s, and found the combination with 25s perfect for 80 mph Speed Limit events. My preferred engines were the pre-ABN OS Max 25 FSRs, when they were actually ABC. With an APC 8-4 prop, and a bladder tank, they fly about as well as the eastern European ARF F2Ds that have such very expensive F2D 15s on them (wide bladed 7-4 props on those).

ChrisSarnowski · « **Reply #2 on:** October 05, 2008, 04:50:28 PM »

Yeah, the OS 32sx is a nice engine. OS has replaced it with the 35ax this summer, though. It's a touch
heavier than the 32sx.

phil c · « **Reply #3 on:** October 06, 2008, 11:09:13 AM »

If you use a larger engine, you need a larger plane. The Gotcha 550, with 550 squares and a 54 in. span will handle an 8-9 oz. motor. The Evo 36 is heavier, so you'd need to add some squares and even more span. The FP25's(if you can find some) and the LA 25 work pretty well on smaller planes like a standard F2D ship. Most of these motors are fitted relatively loose at the top of the stroke and tend to be hard to start hot.

Some places allow F2D 15's on .015 lines. They work quite well. If you have to fly them on .018 lines they are a handful though. Most of the 15's I've seen fly haven't been tuned to work well on 60 ft lines. They are way too twitchy for most people and are prone to turning a full control loop when you want to make a wide, sweeping pass.

ChrisSarnowski · « **Reply #4 on:** October 08, 2008, 07:57:16 PM »

Most of the guys around here are running 32's with a few 25's and 40's thrown into the mix. The guys running the 25's use smaller ships and they turn on a dime. I'm using the Gotcha 500 cores on my ships with the previously mentioned Magnum XL32 and TT Pro36.

Out of curiosity I weighed an OS 32sx, Magnum XL32, and a Thunder Tiger Pro36. These came in at 8.1oz, 8.1oz, and 7.9oz respectively. These weights are without muffler, NVA, R/C carb, or venturi. Looking over on SSW, I see that the Evo 36 should weigh around 8.1oz similarly stripped down.

I am wondering the quality of the bearings and sturdiness of the crankshaft used in the EVO 36. I also wonder if the porting changes made for the C/L stunt conversion make it better or not for combat.

Oh yeah, we are using the odd 72 mph rules...

ChrisSarnowski · « **Reply #5 on:** October 15, 2008, 06:24:09 AM »

Hey Phil and One-Eye,

I do appreciate the comments you've both made on 25's and weight of the larger engines. I'll keep this in mind
when I get my "game" up to the next level.

Phil, I like the discussion/analysis of wing and span loading on the Corehouse web site. I'll be weighing my planes
and seeing where they stand.

-Chris

phil c · « **Reply #6 on:** October 28, 2008, 09:54:02 AM »

The Evo 36 weighs 247 gr. bare(8.36 oz) not a killer amount of weight. The stunt timing should make the motor more flexible running than the others, more tolerant of slight mishandling of the needle and more tolerant of different props. The Magnum 32/36 are close clones of the Evo. The crankshaft will interchange, even the cylinder will fit, but the Magnum uses a head on top of the sleeve arrangement and the Evo uses the more traditional head into th cylinder arrangement. That is probably why it is a bit heavier, the sleeve is about 1/4 in. longer.

ChrisSarnowski · « **Reply #7 on:** October 29, 2008, 09:16:55 AM »

Phil,

Good info on the Evo 36, thanks. Sounds like the crankshaft is robust enough for SLC use.
I see that you like the stunt timing of the engine for easier handling. I read elsewhere that
the C/L liner doesn't have a boost port like the R/C liner - do you feel that helps or hurts
its use for combat?

-Chris

phil c · « **Reply #8 on:** October 31, 2008, 10:56:11 AM »

The boost port mostly functions for better scavenging at high rpms. If you can get an EVO to try, use the usual 9/4 prop. It should turn it around 15,500 in order to hit 75 mph. on one of the bigger planes. Try doing some really tight consecutive eights and see how the rpm holds up. That is where the lack of a boost port may show up. At stunt rpms(8-10K) the boost port doesn't seem to do anything helpful.

Jim Carpenter · « **Reply #9 on:** February 02, 2009, 03:54:49 PM »

First off, speed limit was started years ago by Steve Sacco, he drew up the rules and Neil Simpson refined the rules occasionally. Steve called it Geriatric Combat and they call it GX (personally I hate that name), it should just be called speed limit combat, 75 mph or below. Our rules call for 73 mph which is 3.5 seconds per lap, however if both contestants are flying the same speed up to 75 they let it go. As far as engines I've been running OS 32 SX for around 8 years, it's a wonderful engine and it's a down right shame that OS discontinued them (of course, you had to modify them from RC to CL); they start and restart excellent and run equally as well on hard tank or bladder, 9/4 for hard tank and 8.75 for bladder, 10% fuel, K&B 1L plug works fine. Lately I've been playing with S/T 34 from China (it is made far better than the Italian version), it weighs the same as the OS 32 and comes ready to run in CL version for $70 from Towers; it is a ringed engine but this is not a problem (in fact, in case of a rebuild it could be a plus). First one I ran, took it out of the box, installed the supplied venturi and nva, open the needle 2.5 turns and that where it has run to this day (a good cheap engine). As far as airplanes, naturally I prefer my Yankee Nipper design, this is a very tough airplane ( drive it straight in the ground, change a prop and go up again), if you break the wing cores simply replace cores. More information on this can be found on the New England website.
By The Way, speed limit combat has replaced AMA Slow, so everything that's flown on .018 lines regardless of engine size and the pull test is 35 pounds.
Jim Carpenter

Joey Mathison 9806 · « **Reply #10 on:** February 02, 2009, 05:29:33 PM »

can you post a link to the new england web site?

Jim Carpenter · « **Reply #11 on:** February 02, 2009, 09:00:41 PM »

The website is www.homestead.com/necn

Joey Mathison 9806 · « **Reply #12 on:** February 04, 2009, 05:00:56 AM »

thanks Jim

dave siegler · « **Reply #13 on:** February 04, 2009, 08:44:04 AM »

Magnum 36's and 28's are on sale

http://www.hobbypeople.net/prdcls/eng2s01.asp

I don't need another engine but if you did this might be the time.

Dave

walter weatherford · « **Reply #14 on:** February 05, 2009, 12:54:49 PM »

Quote from: Jim Carpenter on February 02, 2009, 03:54:49 PM

First off, speed limit was started years ago by Steve Sacco, he drew up the rules and Neil Simpson refined the rules occasionally. Steve called it Geriatric Combat and they call it GX (personally I hate that name), it should just be called speed limit combat, 75 mph or below. Our rules call for 73 mph which is 3.5 seconds per lap, however if both contestants are flying the same speed up to 75 they let it go. As far as engines I've been running OS 32 SX for around 8 years, it's a wonderful engine and it's a down right shame that OS discontinued them (of course, you had to modify them from RC to CL); they start and restart excellent and run equally as well on hard tank or bladder, 9/4 for hard tank and 8.75 for bladder, 10% fuel, K&B 1L plug works fine. Lately I've been playing with S/T 34 from China (it is made far better than the Italian version), it weighs the same as the OS 32 and comes ready to run in CL version for $70 from Towers; it is a ringed engine but this is not a problem (in fact, in case of a rebuild it could be a plus). First one I ran, took it out of the box, installed the supplied venturi and nva, open the needle 2.5 turns and that where it has run to this day (a good cheap engine). As far as airplanes, naturally I prefer my Yankee Nipper design, this is a very tough airplane ( drive it straight in the ground, change a prop and go up again), if you break the wing cores simply replace cores. More information on this can be found on the New England website.
By The Way, speed limit combat has replaced AMA Slow, so everything that's flown on .018 lines regardless of engine size and the pull test is 35 pounds.
Jim Carpenter

I thought 2.5cc engines were allowed to use 0.015 lines?

Paul Smith · « **Reply #15 on:** February 05, 2009, 02:13:28 PM »

Quote from: walter weatherford on February 05, 2009, 12:54:49 PM

You'r right, Walter.
If you chose to run a 15 against the bigger engines you can use .015" lines, unless the local organizer ammends the rules otherwise.

Author Topic: speed limit combat engines (Read 3878 times)

ChrisSarnowski

speed limit combat engines

Just One-eye

Re: speed limit combat engines

ChrisSarnowski

Re: speed limit combat engines

phil c

Re: speed limit combat engines

ChrisSarnowski

Re: speed limit combat engines

ChrisSarnowski

Re: speed limit combat engines

phil c

Re: speed limit combat engines

ChrisSarnowski

Re: speed limit combat engines

phil c

Re: speed limit combat engines

Jim Carpenter

Re: speed limit combat engines

Joey Mathison 9806

Re: speed limit combat engines

Jim Carpenter

Re: speed limit combat engines

Joey Mathison 9806

Re: speed limit combat engines

dave siegler

Re: speed limit combat engines

walter weatherford

Re: speed limit combat engines

Paul Smith

Re: speed limit combat engines