Max Speeds with Cardboard

[SolarYellow]

Assuming you're using the Apogee F10. If you're not, you should be.

I would do a flutter analysis to determine the minimum thickness carbon fiber fins that would not flutter, and epoxy them directly to the motor case. See the other threads on here (H13 thread from late last year) for ideas about how to package recovery and avionics in the nose.

1.21-in OD cardboard won't come close to the performance of a "true MD" setup.

Stick around and read for awhile.

 

[MeatNTaters]

I do have the Apogee F10 which would be used for this. I contacted the record committee and they stated that you can not epoxy fins to a motor case, it was my first idea.

 

[SolarYellow]

Apogee sells a 29mm thin-wall tube that is lighter than the thick MMT. It's what the Aspire kit is made from. They also sell nose cones to work with it. I believe it's as close as matters to the same tube as Quest 30mm. Balsa Machining also sells tube they call out as Quest 30mm and eRockets has some Quest 30 in stock. Quest nose cones might be more efficient at the speeds the F10 will reach. You can buy a Quest America kit from AC Supply to get a chunk of the tube and a nose cone for cheap.

 

[Art Upton]

Thank you folks. I am wanting to attempt the F class altitude record using 29mm thick wall for a minimum diameter. I have a plastic nose cone which there will be a FG bulk head to hold my sled for the telemetrum. I plan to use 1/16 fins that are swept with a layer of 1.5 oz FB tip to tip layup. OR should I do 2?

F class altitude should be done with a min diameter thin wall tube and the lightest nose cone you can find.
You should use a low thrust F that does not get near transonic at all.
Your fins need to be light, not heavy.

It should look just like a C or D class Altitude record holder rocket.

 

[SolarYellow]

I do have the Apogee F10 which would be used for this. I contacted the record committee and they stated that you can not epoxy fins to a motor case, it was my first idea.

Not questioning your report, just wondering whether this is Tripoli or NAR?

 

[Glasspack]

I flew a 38mm LOC craft tube and plastic nose cone to about 1.6-1.7 mach on a J570.
The tiny batteries overheated and could not fire the charges but still had data on the chip even with the board broken in the crash. Acme Fin can that Wile-E ordered for me

Here is what it looked like on recovery after seeing the Wile-E-Coyote Mushroom cloud on the playa about 3/4 mile away to the north east. Kraft tube pushed into the hard playa and pushed the motor casing out the back.

[FYI I am not that Fat any more like in this photo or the video]

View attachment 587949

Wow Art ....That is impressive !

 

[Mr G]

Launched and successfully recovered an Estes Partizon on an AT I200. The JL Altimeter 2 indicated over Mach 1 but OR calculated 561 mph - still pretty fast for that thin wall tubing. https://www.rocketryforum.com/threads/loc-vulcanite-vs-estes-partizon-build-challenge.66012/page-4

 

[ljwilley]

Are you trying to break the NAR record or the Tripoli record?

 

[mbeels]

Here is another example of a cardboard rocket going for speed:

https://www.rocketryforum.com/threa...-on-level-1-motors-with-modifications.159420/
https://www.rocketryforum.com/threa...with-modifications.159420/page-4#post-2120702

 

[MeatNTaters]

This is for the Tripoli record. I've done some simulations and it looks like it will be right around mach 1 with my set up so the theory of trying to keep it below that doesn't look promising. The record holder, I believe, was right around mach using DIY fiberglass components. I was going for lite weight but still something that could hold up to mach which is why I went with thick wall cardboard tube. Nose cones that are hollow in a 29mm are hard to find. I went with a plastic. I know I could have bought FG or a PML urethane but I wanted hollow to allow room for my Telemetrum. I will likely have to add nose weight but I am still working through the design as I build it. I plan to launch at Airfest so there isn't a big hurry. If I did my calculations correctly my fin design has a flutter analysis of 2460 mph so I should be good there.

 

[Initiator001]

Charles E "Chuck" Rogers, former TRA President, worked on the X-33 project at Edwards AFB in the 1990s.
He told me the greatest impediment to performance was mass (weight). Sure, fill in tube spirals and all gaps, small fin fillets, tower launch, etc.
No paint or finishing of the model.
Using his advise I flew a minimum diameter model using Estes BT-20, powered by an AeroTech D21W (Actually a D16W) to Mach 1.019. This was before there were small on-board electronics available. The model was flown at night with multiple film cameras taking long exposures with a spinning wheel in front of one of the cameras turning at a known RPM.

I posted about this event in the past on TRF and I expect it is still here, somewhere.

 

[SolarYellow]

AFAIK, the prohibition on fins glued to a composite motor case is an Airfest/Kloudbusters thing, not a Tripoli thing. The language prohibiting fins attached to the case seems to be based on the notion that the motor case will be metallic, not composite.

Aluminum Rockets at Argonia

Rockets launched at Argonia may not be constructed of all aluminum or any other metals. Aluminum fin cans or nose cones will be permitted only if required to ensure structural integrity of the rocket during a high-performance launch. Absolutely no aluminum airframes or fins attached directly to motor cases will be permitted under any circumstances. Please contact the KLOUDBusters prefect for further details.

Might be worth reaching out for clarification. This is the only relevant rule I find in Tripoli's competition rules:

2.9	No modification to certified motor hardware is allowed.

Is gluing fins to it a modification of the hardware? Others glue boat tails around the nozzle and are credited with Tripoli records. There have certainly been rockets flown with fins glued to composite AT cases with the intent of getting the record.

Also, Brothers, Oregon is ~3400 feet higher than Argonia, so it seems like something of an uphill battle to beat this guy's record there:

https://www.tripoli.org/content.aspx?page_id=1537&club_id=795696&item_id=493473