Limited B Rules as Submitted to Board

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Ed Kettler
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Post by Ed Kettler »

Scott, Travis and Jimbo,

Thanks for getting this submitted! I really know how much effort, sweat and blood goes into this process. I'd like to have a conversation about rationalizing/combining some of the engine rules so there is conistency (as much as possible) between Limited B and 2548 events.

Great effort!
Ed
sgilkey
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Limited B Rules as Submitted to Board

Post by sgilkey »

Here are the limited B rules as submitted to the board, requesting Provisional status. Thanks to Travis and Jimbo for taking the lead on this and laying a lot of groundwork.

Proposed rules for a Limited B class, updated November 30, 2004 for the consideration of the Executive Committee towards creation of a Limited B provisional class. Limited B Rules Committee is Tim Feathers, Mike Fredricks, and Scott Gilkey.

1. With the exception of the following requirements, all RCCA Open B class rules and scoring will be used.

2. Engine: Single, stock engine of maximum .29 cid. The engine must not be altered from factory or stock condition, other than allowable modifications listed below. Engines used must be classified by the manufacturer for use in flying R/C aircraft. The engine must be complete with a stock R/C carburetor and stock muffler. The carburetor must be fully functional via servo operation. The port (crankshaft and bypass) timing of the engine shall not be altered from the factory configuration.

Allowed engine changes:

a. Any or all external engine bolts may be exchanged.
b. Bearings, gaskets, and other engine seals may be replaced or substituted.
c. Any “stockâ€
sgilkey
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Post by sgilkey »

Ed, that would be a great idea. We tried to be very consistent with 2548, for example on the props. We really think the MA 10x4 is the way to go, but left the APC 10x3 in there until we can aquire more data- 2548 will help a lot in that regard, and after more experience, we can make a decision to keep or drop the 10x3. We tried also to keep things such that just about any B ship can compete with just a muffler and prop swap. Hopefully these approaches are correct, as we gain experience we can tweak as necessary!
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Post by Bad Dawg »

I think this is great. I plan to only make long trips to Limited B and 2548 contests this year. Maybe I can convince my family a trip to Texas would be a good vacation this year.
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Post by jj »

Looks good to me. Especially like the 72" exception so I don't need to build new wings this year.

Why is there no interest in wood props?

The APC run great but are fragile, more so than a wood prop (IMHO).

The AMS are just not that efficient and up here at 5800ft a MA10x3 does just about nothing. the 10x4 is only marginally better.
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Ed Kettler
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Post by Ed Kettler »

JJ,

We're trying to keep things simple for the pilots and the CD by taking out some of the variables. I could see a 'high altitude' prop being allowed if you folks in CO and the Idaho/Montana guys can do the testing and provide us some baseline data. The restriction might read like "any contest held at or above 4000' MSL could substitute to the high altitude prop as long as everybody flying the contest got to use the same prop." The prop would have to try to keep the speeds in the 50-55 mph range so we keep the carnage down.

The above is just an idea, and not a commitment to make any changes. If you think it is worth it, then you guys need to work through a testing program that evaluates the props/speeds/rpms and comes back with a recommendation for the 2548 and Limit B communities.

I haven't seen anyone use a wood prop in combat, so I don't have an answer for you there. Sorry.

Take care!
Ed
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Post by Jimbo »

Thanks Scott! I LOVE it.
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lightning
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Post by lightning »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by sgilkey</i>
<br /> We tried also to keep things such that just about any B ship can compete with just a muffler and prop swap. Hopefully these approaches are correct, as we gain experience we can tweak as necessary!
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">Er, Scott - did you really mean "B" ships or was typing a "B" about five minutes quicker than "2610"??
sgilkey
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Post by sgilkey »

Keith, the intent was to allow just about anybody who has a B-legal ship to compete in Lim B with a prop and muffler change, that's why we went 3.25# instaead of 3.5# min wt., for instance. Also why we did not restrict to .25 cid.

On the props, a possible wide-blade prop that might work at high altitudes and be included on the list would be the Kavan yellow prop, I think that one is available in a 10x4 size?? Open to suggestions on wide-blade props that would work at high altitudes. We want to avoid opening up props too wide on the off chance that someone will find a rev-up 10x3 or some strange obscure prop that has amazing performance but nobody can find. But if there is a prop like the Kavan that is fairly readily available, performs well at altitude, and is no better at sea level, it could work well in the rules. Or, as Ed suggests, a high-altitude prop clause could be inserted. Maybe you guys just need superchargers- we could add a clause allowing blowers or turbosuperchargers above 4000'??
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Post by Jimbo »

I assume points will be kept for Limited-B after the 1st as was done in SSC. Right?
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Post by MLaBoyteaux »

Hi Jimbo,
I guess it depends on the board approving Limited B as a class, but in anticipation of both Limited B and Scale 2548 becoming provisional for 2005, I added them to the webpage we use to input scores.

Once the board approves the requests for the class, I'll add links to the NPS section so we can list the Limited B and 2548 scores just like SSC.
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Post by Jimbo »

Thanks Mark.
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Post by jj »

I don't think we need a turbo supercharge above 4000', but now that you mention it......

We have done a bit of testing up here already and if the weather holds for tomorrow we will try out Lim B again with a few different prop combinations. I will be trying a wood 10x4 as well.

Wood props work very well and in cold temps over the next few months, they don't get brittle like the APCs. We'll let you know what seems to be reasonable out here.

I have no issues with going to a MAS or APC when plowing through all that thick air.
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Post by lightning »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by lightning</i>
<br /><blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by sgilkey</i>
<br /> We tried also to keep things such that just about any B ship can compete with just a muffler and prop swap. Hopefully these approaches are correct, as we gain experience we can tweak as necessary!
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">Er, Scott - did you really mean "B" ships or was typing a "B" about five minutes quicker than "2610"??
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">Sorry Scott, my bad. I thought this was a 2548 thread for some reason. No issue!![:I][:I]
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