Bruce's new project

[hagent]

Just wondering what was Bruce's record anyways?

[Stephen H]

New Zealand land speed record and a pulsejet land speed record..

i know valved pulsejets go though valves fairly fast but they are more effecient so wouldnt it make sense to make two 200lbs valves jets and they would take up less space for aerodynamics... and every timed run or important run you do just put in a new set of reads?

[hinote]

New Zealand land speed record and a pulsejet land speed record..

i know valved pulsejets go though valves fairly fast but they are more effecient so wouldnt it make sense to make two 200lbs valves jets and they would take up less space for aerodynamics... and every timed run or important run you do just put in a new set of reads?

This is a good opportunity to clear up a major misconception regarding the comparative performance of valved vs. valveless pulsejets:

There has never been a valved pulsejet that can be compared with the (fuel) efficiency of the best of the valveless pulsejets.

We're talking TSFC here; that's the amount of fuel burned, to produce a specific amount of thrust. The conventional scale of measurement is "pounds (or kilos) of fuel consumed per pounds (or kilos) of thrust, per hour". The units are expressed as lb/lbf/hr., or kg/kgf/hr. The resulting TSFC number is the same.

To find this number for a particular pulsejet, operate the engine at a constant thrust, for a specified period of time. Measure the amount of fuel used during that time. Correct the time period to the hour, and apply the same multiple to the fuel usage.

For example: Let's say an engine is operated for 10 minutes, while producing 10 pounds of thrust, and consuming 3.333 lb of fuel. Multiply the run by the factor to make it one hour (x6); multiply the fuel consumption by the same factor, and you get 20 lb of fuel consumed, for one hour.

The TSFC number is then 2.0-- 20 pounds of fuel consumed, while the engine is producing 10 pounds of thrust, during a period of one hour.

No valved pulsejet has ever operated at a TSFC of less than 2.0, as far as I know (anybody out there--please correct me if I'm wrong).

OTOH valveless pulsejets have been operated at TSFC's of less than 1.5. I have personally operated 3 valveless PJ's that have achieved significant improvements over the 2.0 number.

With determined development, I believe it will be possible to produce a valveless PJ that can break the magic 1.0 TSFC number. Issues of fuel injection, augmentation and radiant heat recovery will make this possible--along with the inherent efficiency of the valveless design.

Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."

[me933]

does anyone know what speed he's aiming for? 250mph+?

[Bruno Ogorelec]

There has never been a valved pulsejet that can be compared with the (fuel) efficiency of the best of the valveless pulsejets.

Thanks, Bill. An important point and often ignored. A long time ago (like 60 years or so) Reynst said that having valves on a pulsejet was inherently inefficient. The SFC numbers prove it neatly.

[ZSartell]

It may be far fetched but check out my site. I learned a long time ago that even the most far fetched ideas can come true, you just never know. The problem is that the picture of the drag kart Bruce has shown us is not the kart that he is going to attempt the record with. It is going to be with more than 2 engines. We will just have to wait and see.

http://mywebpages.comcast.net/ZSartell/


Here is the last engine I built for sale on E-bay. I need the extra room and right now the extra money. Thanks.
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... eName=WDVW

[marksteamnz]

http://www.interestingprojects.com/

Road test photos of the beast.
Interesting the words say loss of phase lock causes problems needing a divider between the LH PJ's but the picture appears to show them staggered, or am I seeing phantoms?

NB a dragster shape / chassis are used on the dry lakes in the Lakester class with great success. Similar needs, very fast in a straight line.

Cheers
Mark Stacey
www.cncprototyping.co.nz

[Bruno Ogorelec]

Interesting the words say loss of phase lock causes problems needing a divider between the LH PJ's but the picture appears to show them staggered, or am I seeing phantoms?

If they are staggered, they are nowhere near staggered enough.