F Impulse 24mm 2 Stage MD Rocket

[n27sb]

Just about finished with an F Impulse 24mm 2 Stage MD rocket. This project started simple but did not stay that way. All of the components are scratch built. Features include parachute recovery on the booster, Airstart on the sustainer, GPS, And Dual Deploy recovery on the sustainer.
Both the booster and sustainer use composite motors. Total impulse is a tad under 80ns.
Hope to fly it on the 20th.
Rocksim projects about 6k if I put my usual handicap figures in. Weight w/o engines but ready to fly is 180 gr.

 

[mbeels]

Awesome, good luck! Are you launching from a rail, or using a tower?

 

[n27sb]

I usually make some very small and thin rail lugs. I'll put 2 on the booster and none on the sustainer. I have never gotten a straight flight out of a tower with a 24mm long skinny rocket.

 

[n27sb]

Had a good day at TTRA Tripoli launch near Plant City, FL.
Loaded the 24mm 2 stage with Aerotech F44-4 in the booster and an Apogee E6 in the sustainer.
There is the new Apogee simple timer in the booster that fires the sustainer motor. Separation is done by the upper stage lighting. Motor ejection deployed the booster.
We had great conditions with clear skies and maybe a 1kt wind
Liftoff and boost was dead straight and lasted 1 second. 2.1 seconds into the flight the Simple timer lit the sustainer. About a second later the booster motor ejected the booster parachute.
The sustainer Apogee E6 burned for almost 6 seconds or until it was out of sight. Dual deploy was handled by An Altus Metrum Easy mini. The sustainer was found using an Eggfinder GPS Mini.
Paperwork was filled out and signed by the Prefect and RSO for a Tripoli 2 Stage altitude record.

 

[lowga]

Congratulations on the record! Great looking rocket, Steve. You've got mad skills for sure.

 

[BABAR]

Had a good day at TTRA Tripoli launch near Plant City, FL.
Loaded the 24mm 2 stage with Aerotech F44-4 in the booster and an Apogee E6 in the sustainer.
There is the new Apogee simple timer in the booster that fires the sustainer motor. Separation is done by the upper stage lighting. Motor ejection deployed the booster.
We had great conditions with clear skies and maybe a 1kt wind
Liftoff and boost was dead straight and lasted 1 second. 2.1 seconds into the flight the Simple timer lit the sustainer. About a second later the booster motor ejected the booster parachute.
The sustainer Apogee E6 burned for almost 6 seconds or until it was out of sight. Dual deploy was handled by An Altus Metrum Easy mini. The sustainer was found using an Eggfinder GPS Mini.
Paperwork was filled out and signed by the Prefect and RSO for a Tripoli 2 Stage altitude record.View attachment 421203

Congrats on successful flight and record (s?)

Am I reading it right, the two stage record is less than 500 feet greater than the single stage?

 

[n27sb]

Am I reading it right, the two stage record is less than 500 feet greater than the single stage?

That is correct. Several reasons:

The single stage F was a 29mm vs a 24mm. After waiting 6 months for a good launch day at a Tripoli witnessed launch I finally flew it with a mild wind.
At that time there was no 24mm full F available. Even the 29mm Apogee F10 is less than 80ns.
In the 2 stage I went with a 24mm frame and could get almost a full 80ns combination.
Also conditions were perfect.

That's the thing about these altitude attempts, All factors in the hardware and launch conditions have to come together at a launch with the appropriate TRA officials to verify the launch.

I feel that is about 50% skill and 50% luck.

The original single stage Tripoli F was set with and engine that met or may have exceeded 80 ns.

I will re-attempt the single stage when the opportunity comes around.

 

[BABAR]

Thanks for the explanation.
In any case, great accomplishment!

 

[n27sb]

Thanks

 

[cerving]

Even though it gives up a few n-s to the F10, I wonder if and MD using a CTI 24mm motor would end up going higher since you could reduce drag significantly. Sounds like fun to play with...

 

[n27sb]

Even though it gives up a few n-s to the F10, I wonder if and MD using a CTI 24mm motor would end up going higher since you could reduce drag significantly. Sounds like fun to play with...

Even though the CTI F30 LB comes in at only 73.1ns it has a chance at 6500’. I tried to fly one at the same launch. Unfortunately one of my launch lugs failed on liftoff. That falls under that 50% side of skill or lack of. Thus the motivation for a tower.

 

[caveduck]

Good job - fun stuff! Maybe spoiler-ing my own plans here, but piston launching an F10 or E6 looks feasible and should produce a noticeable gain, especially on a lugless model. At a recent NARAM, people were flying E Eggloft Altitude using E6's on pistons and several flights cracked (snort) 1 km. We'd have to explore whether the likely piston gain exceeds the F10 base drag increase. Another try would be staged E6's with piston assist and a tower to get it up to stable speed before launcher exit. Some of the E egglofters were being flown on naked 2m pistons, so I think E6/E6 should be possible.