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Ed, one mistake many people make with the Supertrapp is to run too many disks. I used a 3-1/2" version inside a standard exhaust on a highly modified Kawasaki Z1. (900cc) The engine was bored to 1075cc, cammed, ported, big valves, and high compression. On this engine I was able to run 5-6 disks. It strained a lot of peoples minds as it looked like the pipe was closed up! I calculated the exit area though and it was the equivalent of 2" straight pipe. Remember this is on the 3-1/2" version. This bike ran mid 10's in the quarter mile in 1976. That works out to around 150 HP using on of the dragstrip calculators I've seen. The large car version (5") has a LOT more exit. I believe most people use too many disks when running the Supertrapp. This results in more noise than there should be with NO increase in performance. Now if the system will hold up to the pulses, I'm not sure there. The thing is with the Supertrapp you must be sure you don't over tighten the disk mount screws or the disks will collapse and won't work right. (The old units used to have a center rod with a spring on it to prevent overtightening.) Lastly you MUST MUST MUST safetywire the bolts/capscrews or you will lose them. I suggest at least .040 in. safety wire. FWIW I do believe this system has merit and can work. Protect the belly though since the exhaust exits all 360°!
Bill Jepson
-----Original Message-----
From: Ed Anderson <eanderson@carolina.rr.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, 14 Jan 2008 12:26 pm
Subject: [FlyRotary] Re: Drips? was [FlyRotary] Re: URL for HushPower
Bob, I have a friend (not on the list) who tried them with a 13B on his GlasStar and his opinion was that they did not stand up to the rotary exhaust pounding and did not reduce the noise sufficient to justify the cost. He now flies with a SpinTech
Ed
----- Original Message -----
Sent: Monday, January 14, 2008 3:20 PM
Subject: [FlyRotary] Re: Drips? was [FlyRotary] Re: URL for HushPower
Has anyone tried a supertrap muffler? I ran them back in my motorcycle racing days and was impressed with ther perfrmance and the hush factor.
http://www.supertrapp.com/product_sections/detail.asp?CatID=32&ItemID=549-3019
Bob Mears
Supermarine Spitfire
-----Original Message-----
From: Ed Anderson <eanderson@carolina.rr.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, 14 Jan 2008 2:05 pm
Subject: [FlyRotary] Re: Drips? was [FlyRotary] Re: URL for HushPower
Well, Mark, I tried that. Actually I tried both SS pot scrubbers as well as SS machining shavings. They withstand the heat with no problem, but the shock of the exhaust soon pound them into small pieces that get blown out of the muffler. However, I did not tried stuffing a HushPower II.
Ed
----- Original Message -----
Sent: Monday, January 14, 2008 10:54 AM
Subject: [FlyRotary] Re: Drips? was [FlyRotary] Re: URL for HushPower
Sorry to say, but I agree. I'm thinking of stuffing my HP-2 with SS shavings.
Mark
On 1/14/08, bmears9413@aol.com <bmears9413@aol.com> wrote:
Im real worried about my noise factor. twelve pipes right in front of me. no muffler. each 1 1/2" exhaust pipe actually has a 3/4 hole to exhaust out of. im hoping that will quiet it a bit....but im pretty sure im full of crap....its gonna be toooooo loud.
Bob Mears
-----Original Message-----
From: Mark Steitle <msteitle@gmail.com>
To: Rotary motors in aircraft < flyrotary@lancaironline.net>
Sent: Mon, 14 Jan 2008 9:39 am
Subject: [FlyRotary] Re: Drips? was [FlyRotary] Re: URL for HushPower
The problem with the auger muffler is that everyone said it sounded like a flying weed-eater. It was sometimes described as a flying chainsaw. Not the most flattering description. It wasn't "that" loud, but you could definitely hear me coming from miles out. Maybe that's a good thing?
I guess we'll soon find out what the HP-2 sounds like with no packing.
Mark
On 1/14/08, bmears9413@aol.com < bmears9413@aol.com> wrote:
Mark,
I thought your spiral muffler you built was quiet. Did it turn out to be too loud after you got in the air? Or too much back pressure?
Bob Mears
-----Original Message-----
From: Mark Steitle <msteitle@gmail.com>
To: Rotary motors in aircraft < flyrotary@lancaironline.net>
Sent: Mon, 14 Jan 2008 9:12 am
Subject: [FlyRotary] Re: Drips? was [FlyRotary] Re: URL for HushPower
Ed,
I don't think it was doing this until after shutdown. That makes sense as all the heat builds with no airflow over the muffler. It would probably be wise to put a SS heat shield between the muffler and the fuselage floor. (I had a piece of Zetex installed, but hadn't waited long enough for the RTV to cure and it started coming off during flight. I will try a fresh piece, and wait a little longer this time.
You're probably right on 1 though 4. I suspect the packing material to be fiberglass. I doubt that ceramic would melt that easily.
Mark
Packing, I don't need no stink'in packing!
On 1/14/08, Ed Anderson <eanderson@carolina.rr.com > wrote:
Hi Mark, interesting development. I suspect several reasons you may be the only one to notice.
1. It might be that the 3 rotor keeps the average muffler heat level higher as you have (approx 1/3 more heat energy with the third pulse during the same time interval).
2. Your muffler is pretty close to the exhaust port - less chance to lose heat before the muffler
3. Your muffler is pointed down (mine and I suspect most are more/less horizontal) and therefore provided an easy path for the melted packing to drip down.
4. What does the packing seem like? I would have expected glass or ceramic packing - but, a glass packing would be the more likely of the two to melt.
If this is the insulation packing and it goes, then the shell might get a bit hotter.
----- Original Message -----
Sent: Saturday, January 12, 2008 5:58 PM
Subject: [FlyRotary] Re: URL for HushPower
For rotorheads that are contemplating using (also the mildly curious) the Flowmaster HP-2 "resonator" muffler,
I installed the HP-2 today on my 20B and was able to do a run-up. Bobby Hughes and I both agree that the exhaust tone is much, much mellower with a deeper tone. My Lighspeed ANR headset had no problem cancelling out this low-frequency exhaust tone. While the overall sound level was still pretty significant, the exhaust tone was much more pleasant to the ears. The ear-piercing, glass shattering, nails-on-the-chalkboard, make-you-bleed-from-the-ears, exhaust tone is totally tamed. The 3-blade M/T prop is the primary noisemaker now. The test took place between two rows of hangars, so I feel that DB readings are not very realistic. I'll take those again out on the ramp and post the numbers. If the HP-2 holds up to the pounding of the rotary's exhaust, I'll be a very happy camper.
Mark S.
On Jan 12, 2008 3:22 PM, Ed Anderson < eanderson@carolina.rr.com> wrote:
They are both used stock Rx-7 turbos. one is the older model pre 89 and the second is a later model 91 year. They both appear to be in working condition in no nicks on the blades and they spin. I used compressed air to spin the compressor wheels to they were really whizzing along.
One came with my 91 turbo block and the other was given to me.
Ed
----- Original Message -----
Sent: Saturday, January 12, 2008 3:46 PM
Subject: [FlyRotary] Re: URL for HushPower
Well,
then we just have to keep on looking for a "justification" for you/your area/etc. :)
Just wait, I'll find something! :)
Thomas
How about: "..... I have two turbo sitting in my shop......."
...are they new/used? What's the scoop on them?
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