"Amateur" UAV achievable altitude?

[FirmamentFX]

Hi guys,

What is the realistic max altitude an "amateur" (ie non government or corporation funded) UAV could achieve?

That is a "how long is a piece of string" question I know, but in general terms...?

Is there a theoretical technical limit (Armstrong's line etc notwithstanding)?

Cheers,

Martin

[Unterhausen]

single stage to orbit?
People have lifted UAV's on a balloon, and gotten to nearly 100k feet altitude.
As far as taking off under its own power and going to altitude, I'm not sure.

[FirmamentFX]

Yes sorry - Single stage.

I'm sure there is a method somewhere for combining it with model rocketry to get 2 or more stages (or possibly even attaching "outboard" rockets that are ignited once in the air and then jettisoned), but initially how far up using a single method of propulsion...

M

[ElectroLawndart]

Hi All,

If you check the Tripoli High Power Rocketry Website (tripoli.org) you will see that the altitude records are about 40 to 45K ft. These are most likely airframes that carry only timing and altitude recording equipment as payloads. I can only imagine the difficulty of lofting an 8 lb plus payload.

I don't think that standard black powder rocket motors don't work at high altitudes. I remember a guy that tried to use one as a cut away device on his helium balloon loft. Maybe a hybrid rocket motor...

Anyway, just the designing and building of the booster could be a HUGE engineering challenge.

IMHO it would be a lot better to go with the "low" tech solution of a helium balloon.

It would be awfully cool to get an unmanned aircraft up to and maintain altitude where the "A" in UAV should be in a lower case letter. :-P

Later, All
Dart

[hg1]

85,000 feet - http://members.shaw.ca/sonde/index.htm

======================

actually, after closer reading, it looks like they only got to 65,000 feet

[macboffin]

Hi All,

If you check the Tripoli High Power Rocketry Website (tripoli.org) you will see that the altitude records are about 40 to 45K ft. These are most likely airframes that carry only timing and altitude recording equipment as payloads. I can only imagine the difficulty of lofting an 8 lb plus payload.

I don't think that standard black powder rocket motors don't work at high altitudes. I remember a guy that tried to use one as a cut away device on his helium balloon loft. Maybe a hybrid rocket motor...

Anyway, just the designing and building of the booster could be a HUGE engineering challenge.

IMHO it would be a lot better to go with the "low" tech solution of a helium balloon.

It would be awfully cool to get an unmanned aircraft up to and maintain altitude where the "A" in UAV should be in a lower case letter. :-P

Later, All
Dart Standard black powder rockets will work in space! The only problem is to get them there! (Lots of B.P. rockets in stages?)

[macboffin]

The Boeing "Condor" got to 96.000 ft on propellors, (twin engine, two stage superchargers) several years back. Must have taken a while to get there though! So there is some hope.Maybe solar power like the "Helios is the way to go.

[Tom Harper]

I think Maynard Hills last record was 26, 919. So, something around 25 to 35000 feet is attainable with standard equipment. One of Maynards comments was that it was difficult to get the model back down without gaining so much speed that it disintegrated.

Might be interesting to use a 4 stroke engine with a pair of tuned pipes for supercharging. Could use a waste gate to kill the Q at low altitude and design the pipes to come in at 25000 feet or so.

[Mark Harris]

Good thing about 4 strokes is they generally need less tuning.. which is critical at high alts... you could supercharge straight off the flywheel though, R/C car guys have done alot of this with varying success (i really dont see the point on cars though heh).

The other option is to be on idle motor speed and get towed up by another plane until it starts running out of fuel, then your lean sittings will let you keep running at the higher altitudes without much trouble. Really need at least a 90 size though from what i've read.

[ElectroLawndart]

The Boeing "Condor" got to 96.000 ft on propellors, (twin engine, two stage superchargers) several years back. Must have taken a while to get there though! So there is some hope.Maybe solar power like the "Helios is the way to go.

Paul McCready's Helios got to 96,000 ft a few years back. It used props driven by electric motors powered by solar cells and batteries.

http://www.globalaircraft.org/planes/helios.pl


As for black powder rockets working in a vacuum, I don't know. I would think that the oxidizer that is mixed into the fuel grain should be enough. Would be interesting to fire off some engines in a vacuum chamber.

Dart

[ninja21m]

I think the que3stion should be what is the max acheivable altitude with a glow/gas engine? I relaize there is mixture control issues, but I have heard that WALBRO carbs auto adjust for this.
Any thoughts on this?

[RaptorAP]

399 feet.

[workshop]

Well 399 is certainly the correct answer! :)

For the sake of argument however... ;)

IMO: High altitude on a hobby level seems to be an electric's game.

Jeff