[NSRCA-discussion] Looking For Props & Header

Thu Nov 5 10:17:10 AKST 2009

Bill,

If the plane keeps shedding glow-power related parts, maybe it is trying to tell you something. :-)

(Did I say that???).

Bob R.

--- On Thu, 11/5/09, Bill Glaze <billglaze at bellsouth.net> wrote:

Jerry:
Thanks--do you have any idea about how many r.p.m's it will cost me?  I'm only running 15% fuel, and, as most know, the easiest, (cheap and dirty) way to increase h.p. is by increasing volumetric efficiency, and the easiest/cheapest way to do that is to increase the engine's compression ratio.  Just wondering how much h.p. this will cost me.  But, will probably still try it anyway--the shaking is obscene.
Bill

----- Original Message ----- 
From: Jerry Stebbins 
To: General pattern discussion 
Sent: Thursday, November 05, 2009 1:10 PM
Subject: Re: [NSRCA-discussion] Looking For Props & Header

Bill, it will not vibrate near as much if you install an extra cylinder gasket. ( 2 needed on top of the cylinder) Try it and it will tame the L down to a respectable level. 
Jerry

----- Original Message ----- 
From: Bill Glaze 
To: General pattern discussion 
Sent: Thursday, November 05, 2009 7:54 AM
Subject: Re: [NSRCA-discussion] Looking For Props & Header

In my case, it's a fairly simple problem.  The 1.40L vibrates so much, that the stud unscrews from the head, leaving the header dangling in space alongside the exhaust port.  I have about a foot of Teflon tubing between the outlet of the header, and the inlet of the Hatori pipe. I also have their (NMP) header brace in place to try to help stabilize the header. 
The engine has already, after about 6 flights, broken a Johnson Header; that's why I am trying the NMP.  I got the last NMP Central had in stock, and they said that the person who was making them is not doing so any more. (That's what I was told, anyway.)   The Hatori pipe is sitting on one mount, about halfway back on the pipe, and the whole outfit is free to move back and forth along with the engine movement.  I had hoped that, with the entire mess moving, it would permit the stud to stay screwed in the head.  I'm worried lest the stud strip the threads in the head.  The instructions say that "some people have had the header loosen" and to try a certain type of Permatex form-a-gasket material.  I've used this stuff before when I had a racing engine business, but I certainly never used it in this type of application.
It seems to me that the entire problem is caused by the excessive engine vibration that the 1.40L is known for.
Any help?
Bill Glaze

----- Original Message ----- 
From: Troy Newman 
To: General pattern discussion 
Sent: Wednesday, November 04, 2009 5:39 PM
Subject: Re: [NSRCA-discussion] Looking For Props & Header

I don’t know what you mean by will it stay attached?

The new header is a wrap around style header like the previous NMP and the Hatori 822 style headers. 

All of the 120-170 engines have the same head configuration (meaning same angle)  and same thread size. SO the new header will fit all 120-170 engines.

There is one exception. The 120AC has the air box on the back of the head. This prevents the use of the wrap around style headers on this engine. Other than that they are all the same.

The NMP header was a really good header for the application. When we were using Teflon tubing to connect the header to the pipe it was excellent. The problem was Hatori went to the newer style pipes that the header slides inside of the neck of the pipe with the o-ring. The aluminum tubing used on the NMP header was not as bullet proof in this application. Remember the Teflon when hot would flex. Now the header and the pipe are attached to each other. The header slides inside the pipe and the result is there is still movement but the stress on the thin wall aluminum piping is higher. Breaking, and the header would get a grove worn in it. Actually the o-ring would pinch the aluminum tubing to a smaller diameter and the header-pipe combo would leak. The added stress of vibration and the direct connection many folks would break the header tubing.

The new header is similar to the Hatori in terms of connection to the pipe. So that swedging ( shrinking of the dia at the o-ring)  problem and the leaking should be solved. In my setup its working well on the proto-type headers. Next issue is the tubing being stronger to take the stress of the direct connection. The solution is kind of unique and is working well. Some more testing and maybe a few tweaks and its going to be a very good replacement for the Hatori 822 and 823.

Troy

From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Bill Glaze
Sent: Wednesday, November 04, 2009 9:05 AM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] Looking For Props & Header

Troy:

Will the new header stay attached to the 1.40 L? Bill Glaze

----- Original Message ----- 

From: Troy Newman 

To: General pattern discussion 

Sent: Wednesday, November 04, 2009 12:35 AM

Subject: Re: [NSRCA-discussion] Looking For Props & Header

I don’t believe there is such a prop made as the 18.1-11 Narrow. It doesn’t exist. I may be wrong but I have been involved with running and testing the APC props in the 18.1 series and WPN series.  There is a prop that is designated as just 18-11 and this has a narrower blade than the 18.1-11.  The 18.1 series of props have a very wide blade. The 18-11 is more like a 17-13 or 17-12 in terms of blade shape but its 18in dia and 11 pitch.

I know there is a 16.5-12 I just pulled one out in my box-o-props and it has a profile like a narrow prop very similar to the 17-10N…however it doesn’t have the designation as 16.5-12 narrow. It’s just called the 16.5-12. If you handed it to me with the name scratched off and said it was a 16.5-12 I would have said it was a Narrow.  Same goes for the 18-11 regular it’s a narrow essentially as well.

I don’t know for sure why the “W” designation or the “N” for narrow is left off of some props and added to others. I think it has a lot to do with the equations and program that is used to create the prop profile. 

To sum up the props APC has the prop if it is or has been produced.  I don’t think Fred throws any of the molds away. So if a prop was produced at one time it might be possible with some convincing to get some of them produced again. I have been to the factory where the props are produced. It amazing how they are produced, and the quantity and quality of props produced for a given size.

You may not be asking for it by the proper name/designation….the 16.5-12 (is actually like a narrow) and the 18-11 is like a narrow version of the 18.1-11

As for Headers…..the new header is in testing and is performing well. The jury is still out, we are working hard to insure the bugs are worked out. Right things are going well and real progress has been made in the last couple months. It will be sooner rather than later from the looks of things on the new headers.

I hope this helps answer the questions

Troy Newman

From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of rjo626 at aol.com
Sent: Tuesday, November 03, 2009 8:20 PM
To: nsrca-discussion at lists.nsrca.org
Subject: [NSRCA-discussion] Looking For Props & Header

     Hello all! I'm looking for APC 18.1x11 narrow, and 16.5x12 narrow. Also,

anyone have a good NMP pattern header they're willing to part with / sell? I've 

tried Central Hobbies and APC with no luck. Thanks a bunch!

     Later!

            RJO

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