Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Choppers With JSF Configured Engines?  
User currently offlinePlanelover From United States of America, joined Dec 2001, 321 posts, RR: 0
Posted (11 years 11 months 6 days 5 hours ago) and read 2002 times:

Hey all,
I was checking out a little cut-away of a JSF. The JSF's lift fan is spun from a shaft running into the front of the engine, and the engine also produces thrust out the back of the engine. My question is this, could a chopper use the same type of setup? On the chopper, you could replace the turbo-shaft with a jet engine that has a shaft to main blades being driven off the front of the engine and use the engine's thrust to provide most of the forward motion. You could probably fly at least 300mph.

Well, that's my question based on my little (or no) knowledge.  Smile/happy/getting dizzy

Have fun.  Smile/happy/getting dizzy
PL



6 replies: All unread, jump to last
 
User currently offlineFlyf15 From , joined Dec 1969, posts, RR:
Reply 1, posted (11 years 11 months 6 days 4 hours ago) and read 1974 times:

Helicopters already are powered by jet engines. Thats what a turboshaft is...a jet engine with a power drive coming off the front of it. Also, a turbofan is what the JSF has, a turbojet with a fan on the front of it.

Choppers (at least with current technology) can't fly too much faster than they already do.


User currently offlinePlanelover From United States of America, joined Dec 2001, 321 posts, RR: 0
Reply 2, posted (11 years 11 months 6 days 2 hours ago) and read 1938 times:

Thanks Flyf15. I understand the basic design of turboshaft (which is the same thing as a turbine, right?), turbojet, and a turbofan. I guess I thought there was more difference than what there really is between a turbofan/jet and a turboshaft. Do turboprops blow a lot of exhaust out of the exhaust duct(s) on the side(s)? Why can't choppers use the trust from the jet to help provide forward thrust? Do those choppers (sorry forget what they are called) that don't have a tail rotor direct engine thrust out of the boom or does the boom have a small rotor inside of it?
Thanks again.
Have fun.  Smile/happy/getting dizzy
PL


User currently offlineShaun3000 From United States of America, joined Mar 2002, 445 posts, RR: 0
Reply 3, posted (11 years 11 months 5 days 21 hours ago) and read 1904 times:

Turboprobs do not have near the exaust (nor the exhaust temperature) as regular jet engines. Why? All the energy is used to turn the propellor. Same goes for a helicopter. But it's still nothing to laugh at.

User currently offlineUps763 From United States of America, joined Nov 2001, 199 posts, RR: 0
Reply 4, posted (11 years 11 months 5 days 10 hours ago) and read 1905 times:

Planelover,
Rotor dynamics and cabin structures often have more to do with speed limitations than engine power. Even the difference between in the piston powered R44 and the turbine powered B206 is relatively small. Then when talking about twin engined jet helicopters like the Twin Star, it only cruises between 5-15 kts faster then its single engined sibling. Your question though was to vector thrust out of the rear of the engine also, this would also not work because the speed would be to fast, remember a helicopters Vne is based upon retreating balde stall.

matt


User currently offlinePlanelover From United States of America, joined Dec 2001, 321 posts, RR: 0
Reply 5, posted (11 years 11 months 4 days 23 hours ago) and read 1891 times:

Thanks you all. This is all very interesting. I don't quite understand why turboprops don't have as much exhaust as a jet. Do they run at a much lower RPM? Could someone elaborate on that a little bit?
Thanks, have fun.  Smile/happy/getting dizzy
PL


User currently offlineJsuen From United States of America, joined Aug 2001, 211 posts, RR: 0
Reply 6, posted (11 years 11 months 4 days 10 hours ago) and read 1878 times:

Think about it this way. If you just hooked your car engine to a big fan, you would move quite a bit of air. However, your car engine is hooked to your transmission and your wheels. The exhaust from your tailpipe hardly produces thrust at all, yet the engine is producing the same amount of energy (in theory).

Top Of Page
Forum Index

Reply To This Topic Choppers With JSF Configured Engines?
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
Widebody With Fus Mounted Engines? posted Sun Feb 20 2005 21:56:23 by DAYflyer
747-300 With CF6-80 Engines posted Mon Dec 13 2004 04:47:38 by MrFord
Early Problems With The A340 4 Engines posted Tue Jul 20 2004 16:17:00 by A380900
Can B744s/A345s Take Off With Only Two Engines? posted Sat Mar 6 2004 09:47:38 by StarG
7E7 With Bleed Free Engines? posted Thu Feb 12 2004 01:27:37 by Fly2hmo
DC-10's With Different GE-engines posted Mon Apr 8 2002 23:25:23 by Ganymed
Imagine The A318 With A321 Engines And Wings... posted Sun May 21 2006 20:54:37 by A342
135 Vs 136 Engines For JSF posted Wed Apr 5 2006 01:09:18 by DEVILFISH
Any 767-200 With RR Engines? posted Wed Nov 23 2005 23:07:58 by Socal
Aircraft With "turning And Burning"- Engines. posted Sun Oct 30 2005 22:32:08 by AmericanB763ER

Sponsor Message:
Printer friendly format