Estes Hi Flier XL with a 29mm motor mount

[FunTimesIndeed]

Built this fun guy with the Estes kit. I bought rings from Apogee to fit a 29mm tube into the body tube. Instead of the stock fins I made my own from two thin balsa slices glued together to make a plywood of sorts with thru-body tabs. I covered them in paper and soaked the edges in thin CA glue for a little extra confidence. Glued and filleted with some basic two part epoxy.With the big jump in aft weight, I suspect she will need a little nose cone lead to push the CG forward. Even with the added weight, I have high expectations for this one. The stock parachute has been replaced by a streamer.

 

[FunTimesIndeed]

Going to clear coat it next week maybe.

 

[bjphoenix]

With the big jump in aft weight, I suspect she will need a little nose cone lead to push the CG forward. Even with the added weight, I have high expectations for this one. The stock parachute has been replaced by a streamer.

The fins are fairly large for the original rocket design. (I think the fins are the size they are because this design was upscaled from the BT20 version.) So there is some margin for stability with more weight in the back. I recommend putting this in Open Rocket and making your modifications.
I opened a stock HiFlier XL sim in my version of Open Rocket, changed the fins to plywood and put in a G64 motor. This put the CG almost right on top of the CP so some nose weight would be needed, and without nose weight it predicted 2600' altitude.

 

[86mustang408w]

Cool man, I'm planning on a 29mm build this winter. I recently cut the shoulder off my 24mm test flyer and gave it a bulkhead/eyelet. Definitely will do the same with the 29mm, doing that seems to help the keeping the CP below the CG and more NC weight could be added.

 

[FunTimesIndeed]

Thanks for sharing, gentlemen.

bjphoenix-I am running a chromebook, so Open Rocket looks out for now, but I may put it on my work computer. I was considering buying RockSim, but again I would need to step up my computer.

86mustang408w-That bulkhead seems like a great add when you need forward weight.

In the background of that last pic you can see my Estes Cherokee fitted with a 29mm mount. The coupler that comes in the kit perfectly fits a thickwall 29mm tube. I cut the coupler into three pieces to do the coupling it was supposed to do, along with two points for a motor mount. The stock fins were beefed up with paper and thin CA glue. She was assembled and filleted with epoxy. Using masking tape for retention. Very similar to my Apogee Aspire, just a little bit wider and heavier.

 

[bjphoenix]

Here is a recreation of what I got from OpenRocket previously. I searched the internet for a sim file for the HiFlierXL and started with it. The sim file had a lot of mass overrides and the overall mass came out about 0.6 ounce less than what I measured for my HiFlier with stock 24mm mount. I changed the fins to 1/8" plywood and added 1/2 ounce to the nose cone. With a G40 SU motor installed this is what I get. Your actual total mass and CG location could vary.


Running the sim this is what it gives me. This rocket will disappear from sight at or before 1000ft altitude so most of this flight will be out of sight, and 737 ft/sec is pretty fast.