NASA Orbiter almost lifts off.
06-22-2009, 10:34 AM
#1
NASA Orbiter almost lifts off.
A six year build finally came to an end and test were conducted last Sat. in Clifton TX.
The scalescratch built orbiter was built by Bob Cervenka of Waco with a contract from NASA. Kevin Whitlow(Dallas)and myself (Austin) went to do the flight tests. After a thorough check out of all systems it was determined ready. Taxi tests were good and it was decided to go for it. About a 800 ft take off roll and full up elevator it didn't even get light on the nose wheel. Brought it back and check a few things, another try resulted in the same thing.. Our guess it that it needed a more positive AOA. After all the orbiter was not designed to take off on its own. CG was right on but with the fuel (150oz)ahead of CG and the main wheels so far backto the rear of the fuselage and not enough AOA for takeoff, it wasn't going to happen.
The model is 84 in. long and powered by a JetCat P160 and weighs about 30 pounds.
Kevin got to go to Houston and doa two hour flight of the orbiter in the shuttle simulator before our test flight.
The scalescratch built orbiter was built by Bob Cervenka of Waco with a contract from NASA. Kevin Whitlow(Dallas)and myself (Austin) went to do the flight tests. After a thorough check out of all systems it was determined ready. Taxi tests were good and it was decided to go for it. About a 800 ft take off roll and full up elevator it didn't even get light on the nose wheel. Brought it back and check a few things, another try resulted in the same thing.. Our guess it that it needed a more positive AOA. After all the orbiter was not designed to take off on its own. CG was right on but with the fuel (150oz)ahead of CG and the main wheels so far backto the rear of the fuselage and not enough AOA for takeoff, it wasn't going to happen.
The model is 84 in. long and powered by a JetCat P160 and weighs about 30 pounds.
Kevin got to go to Houston and doa two hour flight of the orbiter in the shuttle simulator before our test flight.
06-22-2009, 10:52 AM
#3
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RE: NASA Orbiter almost lifts off.
ORIGINAL: bcovish
Kevin to go to Houston and do a two hour flight of the orbiter in the shuttle simulator before our test flight.
Kevin to go to Houston and do a two hour flight of the orbiter in the shuttle simulator before our test flight.
Very nice, and great to see dedication to pursue such an unusual project through a very long development. Two thumbs way up !
06-22-2009, 11:10 AM
#6
RE: NASA Orbiter almost lifts off.
but with the fuel (150oz)ahead of CG and the main wheels so far backto the rear of the fuselage and not enough AOA for takeoff, it wasn't going to happen.
Great project.!!!
06-22-2009, 11:17 AM
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RE: NASA Orbiter almost lifts off.
ORIGINAL: Gordon Mc
Aha !! that's why the model was being built - to wangle a shot in the simulator ?
Very nice, and great to see dedication to pursue such an unusual project through a very long development. Two thumbs way up !
ORIGINAL: bcovish
Kevin to go to Houston and doa two hour flight of the orbiter in the shuttle simulator before our test flight.
Kevin to go to Houston and doa two hour flight of the orbiter in the shuttle simulator before our test flight.
Very nice, and great to see dedication to pursue such an unusual project through a very long development. Two thumbs way up !
Nope, I am just a consultant and pilot on this project. Unlike Bob Cervenka (the designer and builder) Iknew how much work it was going to be from the start, and Iwouldn't have the patience to go through all that just for a sim ride.
The taxi tests went very well this time. I am very happy with the ground handling and nice straight track down the runway now.
Isuggested that Bob lengthen the nosegear to increase the angle of attack, and have new brass (or oillite) wheel bushings made for the main gear to replace the nylon ones that are in there now. Ithink with these two minor changes this thing will be ready to fly.
Covish, thanks for posting the pics.
06-22-2009, 12:07 PM
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RE: NASA Orbiter almost lifts off.
Iknow that my Phantom with the pneumatic nose strut will NOT rotate if it does not extend. Maybe he could build a nose strut similar to that.
DR
DR
06-22-2009, 12:30 PM
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RE: NASA Orbiter almost lifts off.
Nice project!
Thrust vectoring also could help to rotate the nose up.. it works very well in any stubborn delta wing thing even with a negative angle of attack on ground and a high thrust line engine mount.... and it would be a scale feature anyway.
Thrust vectoring also could help to rotate the nose up.. it works very well in any stubborn delta wing thing even with a negative angle of attack on ground and a high thrust line engine mount.... and it would be a scale feature anyway.
06-22-2009, 12:51 PM
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RE: NASA Orbiter almost lifts off.
ORIGINAL: DavidR
I know that my Phantom with the pneumatic nose strut will NOT rotate if it does not extend. Maybe he could build a nose strut similar to that.
DR
I know that my Phantom with the pneumatic nose strut will NOT rotate if it does not extend. Maybe he could build a nose strut similar to that.
DR
Gordon
06-22-2009, 01:36 PM
#14
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RE: NASA Orbiter almost lifts off.
ORIGINAL: DavidR
Iknow that my Phantom with the pneumatic nose strut will NOT rotate if it does not extend. Maybe he could build a nose strut similar to that.
DR
Iknow that my Phantom with the pneumatic nose strut will NOT rotate if it does not extend. Maybe he could build a nose strut similar to that.
DR
Isuggested that he lengthen the nose gear strutt (there is extra room in the wheel well for it), stiffen the spring, and possibly put a 1/4" spacer under the nose retract.
With all that done Ithink we can get at least 2-3 degrees of positive on it.
The nylon wheel bushings are also a problem. Taxiing back after each high speed run required 1/2 to 3/4 throttle to get it moving initially, then by the time it got back to us it was rolling normally, so Ithink the nylon bushing are heating up and creating more and more drag as it accelerates. Bob is going to have some brass or oillite bushings installed in it to fix this.
Hopefully these simple measures will solve the issue. If not we will start trying other more complicated (and more expensive)options.
Maybe a CO2 reaction control system in the nose?? ROFL
06-22-2009, 04:22 PM
#19
RE: NASA Orbiter almost lifts off.
Bob & Kevin,
That wheel problem might be solved by installing actual ball bearings... Thats we did on the big F18's... Go to the hobby shop in the car section and you might find the size you need.. whats cool is they have bearings that are flanged... thats what we used. we had 1/4" axles but i don't remember what the outter size was... after putting those on, you can just look at it and it will roll !!!
Just an Idea.... Good luck , can't wait to see it fly !!!!!!
Danno
That wheel problem might be solved by installing actual ball bearings... Thats we did on the big F18's... Go to the hobby shop in the car section and you might find the size you need.. whats cool is they have bearings that are flanged... thats what we used. we had 1/4" axles but i don't remember what the outter size was... after putting those on, you can just look at it and it will roll !!!
Just an Idea.... Good luck , can't wait to see it fly !!!!!!
Danno
06-22-2009, 04:53 PM
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RE: NASA Orbiter almost lifts off.
Nice but its already been done by Terry Lee one of the directors of Wren, it flys very nice, you can read about it in one of the jet mags not sure which one</p>
06-22-2009, 05:07 PM
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RE: NASA Orbiter almost lifts off.
ORIGINAL: Kevin_W
The nylon wheel bushings are also a problem. Taxiing back after each high speed run required 1/2 to 3/4 throttle to get it moving initially, then by the time it got back to us it was rolling normally, so I think the nylon bushing are heating up and creating more and more drag as it accelerates. Bob is going to have some brass or oillite bushings installed in it to fix this.
ORIGINAL: DavidR
I know that my Phantom with the pneumatic nose strut will NOT rotate if it does not extend. Maybe he could build a nose strut similar to that.
DR
I know that my Phantom with the pneumatic nose strut will NOT rotate if it does not extend. Maybe he could build a nose strut similar to that.
DR
06-22-2009, 08:23 PM
#23
Senior Member
RE: NASA Orbiter almost lifts off.
That is too cool. (bcovish) I've been working on an airframe the past 15 years as a glider - never finished it. This all has me thinking now.....
Dan
Dan
deserve all the credit for this operation. All I am is the piss boy - camera jockey - and spotter for Kevin.
06-22-2009, 11:21 PM
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RE: NASA Orbiter almost lifts off.
Hey guys in 1996 I built a shuttle that has pretty scale outlines. I lift it with a highly modified Byron Pipe Dream powered by a quadra 40. It flies true to scale. It will float but if you want it to penetrate you need to put the nose down. The wing span is 36" and it weighs 5 pounds. It sits on the Pipe Dream with the C.G.s on top of one and other . The lift plane is very uncomfortable to fly trying to overcome the drag of the shuttle but it gets the job done.It has been dropped about 120 times since 1996 and it will be out this weekend for our club air show. Here is some video of the drops. http://www.youtube.com/watch?v=P0qwU...e=channel_page http://www.youtube.com/watch?v=HRlwz...eature=related A few months ago I blew my plans up to about the same size as yours. I am going to power it with an AMT Mercury. I will try to get some pictures of it up here for you to see.</p>
