Fliskits Midnight express fubar...

[jerryb]

Mr. Fliss...

quick question... lol

tried to be sneaky today and launch a paper Midnight Express in our streamer duration launch today... forgot It was built for B engines and put a C6-5 in it...

about 40 feet up it started cutting flips and impacted under power about 15 feet from the pad...

rocket was intact after the impact.. and made a great flight on a b6-4 later in the day... then ended up in a pool.. oh well...

perhaps I need more nose weight for the C engines??

later
Jerryb

 

[teflonrocketry1]

What kind of streamer did you use? Did you use a competition streamer that weighs a lot more than the 18 inch paper streamer that is recommended? Was the nozzle on the rocket motor damaged? Did a fin break loose? What kind of paper did you build your rocket out of? Did you paint it?
I have built two FlisKit Midnight Express models and have been looking closely at their stability. 1/2 ounce (14 grams) of clay in the nose cone should give 2 to 3 calibers of stability with the 18" long by 1" wide streamer. It wouldn't hurt to put another 10 grams of clay into the nose cone though. I can't get this design to simulate unstable unless I do something really drastic.

Bruce S. Levison, NAR #69055

 

[lalligood]

What you described sure sounds like an unstable rocket to me...

BTW, the Midnight Express s-c-r-e-a-m-s on an A8-3. I know they are a free paper rocket but it's crazy to think of putting one up even on a B6-4!

 

[jerryb]

I was using about 25 inches of flagging tape as a streamer...

I've built several (over a dozen) of these models out of 90lb or 120lb card stock, and have never had any troubles that werent related to damage. that being said... this one had Absolutely NO damage to the rocket... like I said... later in the day I flew it again PERFECTLY on a b6-4, and again on an A8-3 ( landing in the neighbors pool ended its career so no further testing is possible on THIS one..)

I did not check the nozzle of the motor that performed strangely, someone else picked it up and pulled the motor before I got it back. but it looked fine when I put the ignitor and plug in it.

I put the exact (weighed on a micro scale) amount of weight suggested in the build instructions every time.

I'm thinking I just overdid it with the C6-5 too much thrust for the weight of the rocket...

I dont have rocksim, so I cannot check its simmed performance on the C class engine...

thanks for the input though..

Jerryb

Originally posted by teflonrocketry1
What kind of streamer did you use? Did you use a competition streamer that weighs a lot more than the 18 inch paper streamer that is recommended? Was the nozzle on the rocket motor damaged? Did a fin break loose? What kind of paper did you build your rocket out of? Did you paint it?
I have built two FlisKit Midnight Express models and have been looking closely at their stability. 1/2 ounce (14 grams) of clay in the nose cone should give 2 to 3 calibers of stability with the 18" long by 1" wide streamer. It wouldn't hurt to put another 10 grams of clay into the nose cone though. I can't get this design to simulate unstable unless I do something really drastic.

Bruce S. Levison, NAR #69055

 

[jerryb]

they really jump up there on a b6-4.... whoosh... darn.. where is it...lol..

I'm guessing i'll have to try it again on another one to see if it goes unstable at stock weight.. unless someone can sim me the exact amount of weight needed to stabilize it for the C motors.

later
Jerryb

Originally posted by lalligood
What you described sure sounds like an unstable rocket to me...

BTW, the Midnight Express s-c-r-e-a-m-s on an A8-3. I know they are a free paper rocket but it's crazy to think of putting one up even on a B6-4!

 

[BobH48]

I put the exact (weighed on a micro scale) amount of weight suggested in the build instructions every time.

They may have updated the instructions. The Midnight Express instructions that I printed don't specify the amount of weight for the nose but a balance point instead. I balanced it on the forward end of the range and flew it on a C6-5.... once

Man it went high!!! And it landed way into the woods surrounding the field

So now I have built another one and it flys just fine on A8-3's

 

[slim_t]

I've built at least a dozen ME's, and have launched a few on C6-7's (bye bye), and have never had one go unstable.
But I don't go by a specific amount of weight.
Instead I add weight until the Cg is where specified in the instructions, probably even a little higher.

The rocket holds up fine under C power. I've even gotten one back after a C launch.
My guess is yours was just marginally stable, stable on a B, but not a C, which is what you were probably going for in a competition, just barely stable. A bit more weight would have done the trick. Try another one, they can handle C's.

Tim

 

[jerryb]

will build another few in the near future.. thanks folks..

Jerryb

Originally posted by slim_t
I've built at least a dozen ME's, and have launched a few on C6-7's (bye bye), and have never had one go unstable.
But I don't go by a specific amount of weight.
Instead I add weight until the Cg is where specified in the instructions, probably even a little higher.

The rocket holds up fine under C power. I've even gotten one back after a C launch.
My guess is yours was just marginally stable, stable on a B, but not a C, which is what you were probably going for in a competition, just barely stable. A bit more weight would have done the trick. Try another one, they can handle C's.

Tim

 

[jflis]

Jerryb,

Another thought is that a fin may have bent or flexed during flight due to high speed. It's unusual, but not impossible. I've flown many on C motors (never more than once, i'll admit, as I can never find them againLOL), and have never had a problem.

Also, concerning the stability question, if you have it all prepped for flight, just verify the CG as shown in the instructions and add more weight if needed.

hope this helps!
jim

 

[jerryb]

did NOT check CG before flight... and the fins looked fine... guess it was just one of those "things" lol

I've given probably 30 of the printed sheets for the M.E. out at our club launches.. and so far.. only 1 other member has returned to fly them... I'm going to suggest a club wide launch for our monthly launch...

its really cool to watch people's expressions when you hand them this model to look at... then fire it off... one of the best paper flier's i've had the opportunity to play with

later
Jerryb

Originally posted by jflis
Jerryb,

Another thought is that a fin may have bent or flexed during flight due to high speed. It's unusual, but not impossible. I've flown many on C motors (never more than once, i'll admit, as I can never find them againLOL), and have never had a problem.

Also, concerning the stability question, if you have it all prepped for flight, just verify the CG as shown in the instructions and add more weight if needed.

hope this helps!
jim

 

[BobH48]

I lost another ME just yesterday afternoon. I launched one in my back yard ( 100' X 150' surrounded by trees) on a C6-5 just because my daughter wanted to see a rocket go "really high"

Oh well, I'll just have to make another one

I had been launching cones and saucers and they only go about 100' high so I was getting those back.

 

[jerryb]

Originally posted by BobH48
I lost another ME just yesterday afternoon. I launched one in my back yard ( 100' X 150' surrounded by trees) on a C6-5 just because my daughter wanted to see a rocket go "really high"

Oh well, I'll just have to make another one

I had been launching cones and saucers and they only go about 100' high so I was getting those back.

the ME on a B4 flies great in my back yard... also an A83 will push it up to respectable height