Author Topic: .90 cu in, 30,000 RPM, 7.2 HP custom built nitro engine  (Read 71490 times)

Offline strictlybusiness1

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Re: .90 cu in, 30,000 RPM, 7.2 HP custom built nitro engine
« Reply #315 on: October 26, 2018, 08:27:55 PM »
This is very interesting, considering that  one of the main enemies of any compression ignition engine is detonation.

Jim

Offline DRT

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Re: .90 cu in, 30,000 RPM, 7.2 HP custom built nitro engine
« Reply #316 on: October 26, 2018, 09:01:38 PM »
Isnt it? I thought so too. I knew you'd want to see this.

http://www.aero-news.net/index.cfm?do=main.textpost&id=08312146-cc40-476d-a000-57401f63f5b9

don't want to pull you guys off this interesting thread but Im sure you all will find it quite interesting how detonation is being used as a friend instead of the enemy.  Really cool technology is.

Email you later JA
TTYS

Offline strictlybusiness1

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Re: .90 cu in, 30,000 RPM, 7.2 HP custom built nitro engine
« Reply #317 on: November 25, 2018, 04:35:54 PM »
After testing many different tuned pipe prototypes we can finally show a dedicated chamber for use with 32 to 35 cc displacement gas engines. The bottom two prototypes will be going into production for this purpose. The posted photo clearly shows the difference between what is available on the market & what is necessary in an attempt at achieving maximum HP. A tuned pipes maximum internal volume, compared to the displacement of the engine in question, is definitely one  controlling factor in the design of any tuned pipe!

Jim Allen

« Last Edit: November 25, 2018, 07:51:49 PM by strictlybusiness1 »

Offline Admiral_dk

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Re: .90 cu in, 30,000 RPM, 7.2 HP custom built nitro engine
« Reply #318 on: November 25, 2018, 09:53:04 PM »
It might be the light or eyes deceiving me, but - is the bottom pipe in the picture having a continuously changing angle on the first diffuser cone ?

I ask, because I always felt that this would be the optimum, just like when used for sound (speakers, trombone etc.) or fluid dynamics (turbines etc.), where any kind of sharp edges are usually a no, no ....

Offline strictlybusiness1

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Re: .90 cu in, 30,000 RPM, 7.2 HP custom built nitro engine
« Reply #319 on: November 27, 2018, 06:50:37 PM »
Per,

Yes. We attempted to make a smoother transition from the header pipe through the diffuser sections to the mid-section by adding more pieces. Instead of the standard 2 or 3 sections found on most pipes there are 5 sections in the diffuser section. What is important is that there is no long length flat area from the exhaust window to the mid section of the chamber. The next thing is to CNC machine the sections to eliminate any flat area whatsoever.

Jim

Offline Roger B

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Re: .90 cu in, 30,000 RPM, 7.2 HP custom built nitro engine
« Reply #320 on: November 27, 2018, 07:03:51 PM »
Fascinating  ::)  :headscratch:  :ThumbsUp: There is so much to learn about two stroke engines
Best regards

Roger

Offline Admiral_dk

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Re: .90 cu in, 30,000 RPM, 7.2 HP custom built nitro engine
« Reply #321 on: November 27, 2018, 08:07:27 PM »
Ah and I thought that it was hydroforming as the first photo didn't show the welds of the cones but looked like it was two sheets welded end to end and then "blown up" to shape.

Very nice work none the less  :ThumbsUp:

Offline strictlybusiness1

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Re: .90 cu in, 30,000 RPM, 7.2 HP custom built nitro engine
« Reply #322 on: November 28, 2018, 05:17:55 PM »
Ah and I thought that it was hydroforming as the first photo didn't show the welds of the cones but looked like it was two sheets welded end to end and then "blown up" to shape.

Very nice work none the less  :ThumbsUp:

No Hydroforming but two pieces formed in a mold & then welded together. This is not the best method for making a prototype pipe because it cannot be easily modified or changed. Machined pipe sections are fitted to join inside or outside of their matting pieces. This method makes a completely smooth inside surface & a very strong joint even when the joint is silver soldered. The joint is typically .050" wide with each joining piece's thickness cut in half, typically .010" thick.  This method can also be used when joining sections that have a radius.

Jim Allen

« Last Edit: November 28, 2018, 07:31:01 PM by strictlybusiness1 »