How to Achieve 2500lbs+ Thrust: Ducted Fans, Turbofans, or Other Methods?

[jezym108]

thanks ron
do you know any sites where i can get my questions answered?

i just a have a couple more questions:
can tip jets be used to power a ducted fan?
ie. use thrust from a small jet, get the thrust to the end of the rotors and make it come from holes

the ducted fan doesn't have to produce anything in the region of 2500lbs it would only need to produce around 450lbs from 2 10 foot blades can it be done with 50lbs of thrust coming out of each rotor blade?

i see lots of people making 'backpack' helicopters and many people say they won't catch on because the riders head is so close to the blades, so why can't a mesh cover be constructed around the blades? that would make it safer wouldn't it?

 

[FredGarvin]

You're asking opinions on technologies that are highly experimental and have never seen the light of day on a real aircraft. What kind of answer do you expect? Have you done any research into the background of the Osprey? Look at the huge number of engineering hurdles they had to overcome.

Anyone who tells you absolutely yes or no about your idea is pulling your leg. Your questions need to have serious testing and evaluation to say if they will work or not.

 

[Danger]

Jezym, I'm also very interested in this, but have essentially no knowledge about it. I'm more than happy to continue kicking the **** around with you, but pay close attention to what Fred and Ron are telling you. This is not something that can be even half-seriously dealt with in a round-table discussion. You need very careful professional engineering studies.
There's one thing that I'd like to clarify, just in case there's a misunderstanding on your part. You mention thrust vectoring and ducting and the Harrier as if they are one and the same. Nothing could be farther from the truth. The bird doesn't have a regular engine that is then ducted. The Pegasus engine in the Harrier was purpose-designed for that (and a sister) aeroplane. Those four swivelling nozzles are part of the engine, and constitute its only exhaust outlets. The only way that you could match Harrier performance is with a Pegasus, and you can't pick one of those up at Walmart.

 

[NateTG]

There are pressure jet and ramjet (and I'm sure there's rockets as well) rotor helicopters. You might look at something like http://www.pulse-jets.com/ where people are much more in touch with this sort of stuff.

 

[RonL]

i see lots of people making 'backpack' helicopters and many people say they won't catch on because the riders head is so close to the blades, so why can't a mesh cover be constructed around the blades? that would make it safer wouldn't it?

You might see lots of people talking about Back-Packs, but i don't think very many are making them. This is something i am seriously considering (maybe this summer) experimenting with, i have most of the things needed to start testing some of my ideas.
The main thought is electric, with several methods of storing energy, and transferring it out as thrust, somewhere around 900 BTUs per minute.(20 HP)
But then that is far from what you are talking about.

 

[jezym108]

so ron youre planning on building an electric helicopter?

my idea (i have a lot of ideas) was to redirect thrust from a small jet engine through some pipes so it comes out of the end of the rotors and because its a tip jet there's no need to counteract torque

also ron how do you plan to keep your craft safe it something goes wrong?
would my idea of a mesh around the rotors work?

another thought i had was what if you keep the rotors below the person instead of above their head that would make it safer wouldn't it?

also is it more efficient to have the rotors above or below the rider?

 

[RonL]

so ron you're planning on building an electric helicopter?

my idea (i have a lot of ideas) was to redirect thrust from a small jet engine through some pipes so it comes out of the end of the rotors and because its a tip jet there's no need to counteract torque

also ron how do you plan to keep your craft safe it something goes wrong?
would my idea of a mesh around the rotors work?

another thought i had was what if you keep the rotors below the person instead of above their head that would make it safer wouldn't it?

also is it more efficient to have the rotors above or below the rider?

I posted a video clip of the Hiller flying platform, on another thread. As far as rotors above or below, i would think not much difference.
Mesh will be unnecessary weight, and like NASA even grams will make a difference.
I believe Bell Helicopters patented jet tip thrust from a jet engine several years ago, for a gyro type helicopter.
Safety? cover all your bases before you pull yourself off the ground.

My design ideas cover a lot more than electric, the motor/generator is what keeps things in motion after it has been loaded with energy, and likely, compressed air will have a role as you are talking about.
As stated, some of my thoughts will need testing and may not work in the conditions they will be applied, my biggest struggle will be keeping weight down, without compromising safety.
Some of the fun of being retired, is just messing around doing things you like.

 

[Danger]

my idea (i have a lot of ideas) was to redirect thrust from a small jet engine through some pipes so it comes out of the end of the rotors...

Have you any idea of the complexity of plumbing that kind of stuff through a swash-plate?

and because its a tip jet there's no need to counteract torque

How do you figure that? It might not be the same kind of torque as a regular chopper, but you won't get off scott-free.

what if you keep the rotors below the person instead of above their head that would make it safer wouldn't it?

As long as you don't fall out of your seat...

 

[russ_watters]

If I ever win the lottery, I have a few ideas I'd send to Scaled Composites, along with a check for $10 million to see if they can develop them, but short of that, this thread is just a lot of daydreaming. As said, you need serious engineering help and that isn't something you can get on an internet forum. It takes thousands of hours of design time to answer these questions in a serious way.

 

[FredGarvin]

Please lock this thread.

 

[Danger]

Agreed, but with the encouragement to Jezym to further his interest and studies into the sciences. I see some good potential here, but it needs to be properly directed.

 

[FredGarvin]

Agreed. Well spoken.

 

[jezym108]

hey
thanks for the help guys

i'll be finishing my A-levels this year and plan on doing aeronautical engineering at university