HPR Sim Questions

[Donnager]

The only issue I find is your delay went 12 seconds instead of 7 seconds. Your sim data and delay times are within expected tolerances for your atmospheric and wind settings. Was the temperature really 49°F at Lucerne at launch? This is where flight computer data is critical, actual pressure and temperature, in determining fault issues.

The H100 appears to be under powered, T/W, for your vehicle. I would suggest using either an H219T or H283ST for a higher off the rail velocity.

The colleges seem to buy up all the H100's. Never flown an H100 myself, but I do know that an H219 or H283 will resolve most L1 takeoff issues (soundly).

I hate slow take-offs.

 

[Aeva]

The only issue I find is your delay went 12 seconds instead of 7 seconds. Your sim data and delay times are within expected tolerances for your atmospheric and wind settings. Was the temperature really 49°F at Lucerne at launch? This is where flight computer data is critical, actual pressure and temperature, in determining fault issues.

The H100 appears to be under powered, T/W, for your vehicle. I would suggest using either an H219T or H283ST for a higher off the rail velocity.

Saw this too. 7 seconds (from burnout to apogee) was definitely enough because that was right around apogee.

 

[Spacedog49Krell]

The colleges seem to buy up all the H100's. Never flown an H100 myself, but I do know that an H219 or H283 will resolve most L1 takeoff issues (soundly).

I hate slow take-offs.

I ran OR simulations with motors from G80 to H550, looking for possible OR Cd calculation issues and H100 motor under performance with the OP's rocket design. The OR sims were close to my Excel spreadsheet calculations. The video analysis showed a slow launch, some weathercocking, and the 12 second time delay.

I have never flown an H motor. In the late '70's, I went from G80 to I300 motors.

 

[Donnager]

Consider the sims as guardrails. You can get there, but realize there are other options. H283, 238, 219 are awesome options for L1.

I'd call an H100 a great motor for cert, but it really doesn't have a lot of grunt. I prefer some (haul) ass on my rockets. I don't like worrying about whether the rocket will "clear the tower", or if it will clear slowly and turn into the wind.

I like H-550's, I-500'ish and some J bowling ball motors (1299/1799), and the J800. Got some K's I take a fancy to, as well.

 

[Donnager]

I ran OR simulations with motors from G80 to H550, looking for possible OR Cd calculation issues and H100 motor under performance with the OP's rocket design. The OR sims were close to my Excel spreadsheet calculations. The video analysis showed a slow launch, some weathercocking, and the 12 second time delay.

I have never flown an H motor. In the late '70's, I went from G80 to I300 motors.

Sounds like you've been there before.

 

[rcktnut]

I have RS, what was the weight of your Exel?

 

[Donnager]

Redundant

 

[rcktnut]

Could someone please give me the weight of the rocket w/o motor as in the OR file. Thanks, wish to sim it on RS. The one I have on file weights 36 oz.

 

[Spacedog49Krell]

Sounds like you've been there before.

I've been there for a very long time. I'm now retired, I keep my mind sharp doing analysis for others, with less experience, for the fun of it.

 

[Spacedog49Krell]

Could someone please give me the weight of the rocket w/o motor as in the OR file. Thanks, wish to sim it on RS. The one I have on file weights 36 oz.

1581 grams

 

[rcktnut]

Here is what I got on RS, launched off a 6ft. rail/ rod. I would say if you got 1400 ft. actual altitude pretty much in range to be expected. Motor performance seems to be ok. Your delay was late for some reason.