I have a NIB YS .61 Long stroke RE and a Hatori/Futaba Pipe (Part # Y00030) that is going in a LA-1 (18 years old and never flown).

I need to know what I should do for pipe length and a reminder how to measure. I remember something like glow plug to "fat part" of the pipe but not sure. I'll be running 30% Heli fuel and an APC prop but also need to be reminded of the "right size" for this engine and this plane. 12 x 10 comes to mind?? The plane is a tail dragger so if I need more diameter, es no problema. Just some idears will be great and I can test from there.

Thanks,
Scott

The best info I have is in the "Bolly Book" from the now defunct bolly products company

Link to book http://www.bolly.com.au/book.html

They use to make a range of very cool cabon fibre pipes ect as well as Prop's and Landing gear for pattern


Regards

Johnkpap

just strap it on and go, the I had didnt do any thing as far as pipe length

1. Select your prop and fuel.
2. Install your pipe and header. It's useful to have a friend hold the pipe with a rag.
3. Tach your engine at full bore.
4. Cut 1/4" off the back of your header.
5. Repeat steps 3 & 4 until you notice an RPM increase.
6. Continue the cut & tach routine but only make 1/8" cuts. Stop when no further RPM increase is realized.
7. Add 1/4-1/2" back to your pipe length and mount your pipe.

Congrats on the LA-1!!! Would love to see some pictures...

The Bolly Book is Awesome!! grotto2's info as well...Plus I've attached a copy of the OS Hanno Special manual which has some good info on tuning too (forget the OS specific stuff)...Pay close attention the the "Pipe length-vs-Needle valve" comments as those are key in my opinion!!

Here is some of my personal YS 61 info which may help get you started:

Provided you have the "standard" YS 61R LS (YS0090) then 12x8 to 12x10 on the prop will be good...I personally like the 12x10 which turns @ 10.5k using YS 20/20 fuel, you will probably turn up a bit more with the 30%...The 12x8 just spins up a little too much for my tastes...Now if you have the "AR" version (YS0091) it will swing a bigger prop...

I can tell you my personal starting point on YS 61 pipe length is 20.5"... I measure from the glow plug to the first baffle (ie: the first weld on the Hatori 650 pipe aka: Y00030)...I will shorten from 20.5" in the 1/4" increments as suggested above and normally wind up @ 19.7" as my final pipe length...I'm sure your measurements will be different, I just listed mine for reference...

Good Luck and have fun with your LA-1

Thank you guys for the floods of memories.  I started reading Grotto's post and then Atlanta's and pictures of standing on the hobby shop loading ramp cutting my header 20 years ago came rushing to my brain.  Thank you guys a lot.  That's exactly what I was needing.  Thank you John for the Bolly post as well.  I actually read that tonight (Happy New Year to me) and it's really interesting to see it from a total scientific point of view.  I actually understand the dynamics a little better.

I posted a pic before, Atlanta, in one of the other posts.  You commented but when I have the spinner polished and ready to fly, I'll grab some more and update this thread.  This LA-1 was one of the few planes that I actually built myself (with A LOT of hand holding).  I moved to Arizona and when I moved back to Texas, my best friend had it in exactly the same shape as I left it 18 years ago.  Thanks to Ed V., it's now ready to go with some minor details left to finish.  Now....just to find a paved runway.

Happy New Year and thanks again guys,
Scott

One more thought:

I think most of the guys who were running these engines on 30% nitro back in the day were adding an extra shim to the head to lower the compression some. It's been a while since I've read the Bolly Book and this may be addressed in there?? I know I've read Troy Newman and others mention it. I haven't added any extra shims running the YS 20/20 fuel. I don't think it really becomes necessary till you get to 25% nitro or more. Hypersensitive needle adjustment, blowing glow plugs, overheating, sagging under load in climbs, harsh/lean running despite taking off with a good needle setting; Those are all symptoms of too short pipe length, apparently too high of compression will exhibit similar symptoms...

Please keep in mind I'm no expert!! I'm just passing along stuff I've read or learned from others and maybe a little bit of my limited experience mixed in...

For adjusting a header-pipe, check this article out:



[link]http://images.rcuniverse.com/forum/upfiles/162189/Mk27709.pdf[/link]

Brian

Scott,

Search YS .61 pipe lengths.. Then search for post #1. This should help you..

BL

BL,

Saweet!  Thank you very much for that post.  I'm going to take all these posts in to account.  Thank y'all again.  I love the pattern community...new style and old. 

Scott<br type="_moz"/>