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Propane Pulse Jet - 8/15/2005 10:56:34 AM   
kmorgan


 

Posts: 59
Joined: 9/24/2004
From: , UNITED KINGDOM
Status: offline 		Hi All
In the latest issue of Model Flyer (UK Mag) mention is made of a pulse jet that runs on propane being available in the US for $80. Does anyone have any details or link for a web site please?

Cheers

Kevin
       Post #: 1

RE: Propane Pulse Jet - 8/29/2005 7:54:59 AM   
dennis



Posts: 1292
Joined: 1/7/2002
From: Minersville, PA, USA
Status: offline 		In RC the first turbines were Propane. Notice that they don't use them anymore. One of the reasons is that they are a flying bomb. There were more then one woods set afire by a crashed jet.
Don't think that i'd run out and buy one either. Oh and a kero turbine has already been flown C/L. Cant imagine having the thing spooled up more then 1/4 power, you couldn't keep up with it if you ever hit the throttle. over 300 mph is possible with a large rC jet and I understand that they restrict the plane to under that for safety reasons.
Dennis

(in reply to kmorgan)
       Post #: 2

RE: Propane Pulse Jet - 8/29/2005 2:28:21 PM   
downunder



Posts: 3198
Joined: 10/10/2002
From: Adelaide, AUSTRALIA
Status: offline 		A pulse jet is wildly different to a turbine. Pulse jets were flown on CL long before RC came out and if you'd ever heard one you'd never forget it.

(in reply to dennis)
       Post #: 3

RE: Propane Pulse Jet - 8/29/2005 5:12:46 PM   
JohnBuckner



Posts: 3931
Joined: 12/23/2001
From: Kingman, AZ, USA
Status: online 		Do a search on controlline speed and I think you will find lots of info on Pulse Jets and various fuels used. I beleve the current US record for controlline jet speed is just over 200 with D speed records being very close.

Dennis You are talking two very different engines and Pulse Jets are not normally able to be throttled. Although Pulse Jets have been used in many types of RC aircraft over the years with varying degrees of success. True turbines are just new kids on the block with there own set of precautions and problems not neccessarily related to PJ engines.

I still have and treasure my 1959 OS type 11 Jet but have not run it in many years. In this case it was run on white gas, but many alternatives are used today that I am not qualified to comment on.

John

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RE: Propane Pulse Jet - 8/29/2005 8:02:07 PM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		Kevin:

As John said, you can't throttle a pulse jet. And I agree that propane is far from the best choice for fuel. Just too bothersome to handle.

Further, AMA has had a long standing prohibition against high pressure tanks in a model plane. Possibly the 30 psi or so for propane wasn't thought high enough to be proscribed, or maybe the early turbine fliers got a waiver.

Biggest thing against pulse jets is the sheer noise. Back in the early 60s we did a comparison in Texas. A Dynajet was actually louder than a T-33 running at 100% power.

Bill.

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AMA 25139 - More than 40 years.

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RE: Propane Pulse Jet - 8/29/2005 10:05:54 PM   
Clean



Posts: 990
Joined: 4/19/2002
From: Parkville, MO, USA
Status: offline 		Well that's hardly a problem anymore Bill, I can't think of a place that HAS an operating T-33!

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From Somewhere near Parkville, Mo.
William Crane (aka Mr Clean) Rever Brother #168 Time Man of the Year

(in reply to William Robison)
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RE: Propane Pulse Jet - 8/29/2005 10:48:25 PM   
William Robison



Posts: 20269
Joined: 11/10/2002
From: Mary Esther, Florida, FL, USA
Status: offline 		Well, Bill, for a more modern comparison I'm sure the Dynajet is louder than the a Phanton's pair J-79s too. The Phantom at ful AB might be louder, but not by much.

One of the very few things I know that's louder than the Dynajet is a Saturn 5 at liftoff.

Bill.

_____________________________

Real Airplanes have Two Engines
AMA 25139 - More than 40 years.

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       Post #: 7

RE: Propane Pulse Jet - 8/30/2005 3:20:19 AM   
vicman



Posts: 6209
Joined: 12/8/2002
From: Valdese, NC, USA
Status: offline 		I have a set of prints and have been working on building one for a while. The tube has me stuck for now, I just don't feel like making all the tooling needed to spin it.


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Revver Brotherhood & NMPRA #41

(in reply to William Robison)
       Post #: 8

RE: Propane Pulse Jet - 8/30/2005 12:16:25 PM   
dennis



Posts: 1292
Joined: 1/7/2002
From: Minersville, PA, USA
Status: offline 		Actually I well know what a Dynajet is having had a few of them myself as well as the OS and even the M.E.W. I really didn't read the post correctly and replied to a misguided understanding of what I'd read.
As to the noise of a Dynajet it is actually a low frequency type and as has been discovered low frequency has the ability to transmit noise or sound ouve\r tremendous range. Given that we have had a few of them run up at our field within the last few years it Always brings a smile to my face to hear one of them run.
Dennis

(in reply to vicman)
       Post #: 9

RE: Propane Pulse Jet - 10/31/2005 9:30:55 PM   
blazkowicz


 

Posts: 1
Joined: 10/31/2005
From: Dalton, GA, USA
Status: offline 		for the record, his question was:
"In the latest issue of Model Flyer (UK Mag) mention is made of a pulse jet that runs on propane being available in the US for $80. Does anyone have any details or link for a web site please?"

not
How flammable is propane?
Can someone give me the history of pulse jets?
How loud is a pulse jet?
How does the AMA feel about compressed fuels?

sorry to flame (pun definately intended) but i'm researching the same thing and already know about the hazards and noise, but would like to buy or build one anyway.. and it seems every thread i come across on the net has this same information. off topic history of jets and "look at how much i know" as opposed to answering anything.

well, so i can say i contributed SOMETHING to this thread, heres a link i found that has ALOT of detail on both valved and valveless pulsejets, and even some valved that he claims can be throtled thru a wide power range. plenty of plans and detailed writeups.. plus plans for a no-weld pulsejet... tho i wonder how well it works.... (however its not USA based...)

http://www.aardvark.co.nz/pjet/

(in reply to kmorgan)
       Post #: 10

RE: Propane Pulse Jet - 11/1/2005 3:04:06 AM   
vicman



Posts: 6209
Joined: 12/8/2002
From: Valdese, NC, USA
Status: offline 		Hey Mr. one post. pm me and I will send you the plans to build for your bad self. Then you can contribute your vast experience. What the heck I will even throw in the reed since I have a few extras burned out.


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RE: Propane Pulse Jet - 12/14/2005 3:45:53 AM   
robear1053


 

Posts: 13
Joined: 3/12/2003
From: Omaha, NE, USA
Status: offline 		The only propane pulse jets I have seen have been valveless. Many years ago (when Dynajets were in hobby shops for under $100) I do remember someone marketing a valveless propane pulse jet. I dont know if anyone ever got one to fly but do know they were also sold as jet demonstrator engines to high school shop teachers. If I remember right the thrust was actually quite low... maybe 2 or 3 pounds.
Bob Furr

(in reply to vicman)
       Post #: 12

RE: Propane Pulse Jet - 12/14/2005 2:25:25 PM   
gcb



Posts: 2422
Joined: 10/24/2002
From: Port Ewen, NY, USA
Status: offline 		Dennis,

Did you actually get that M.E.W. to run?

George

(in reply to dennis)
       Post #: 13

RE: Propane Pulse Jet - 12/17/2005 4:24:08 AM   
mathison205


 

Posts: 10
Joined: 11/26/2005
From: las vegas, NV, USA
Status: offline 		ama c/l jet speed record is 204.93 mph held by waltemath and mathison 12/7/2002 not only did i see this record set i was the pilot very cool thing to do on a weekend of fun in the sun. joey

(in reply to JohnBuckner)
       Post #: 14

RE: Propane Pulse Jet - 12/17/2005 9:21:06 PM   
dennis