What's YOUR Preferred Motor Mount Size?

[GaryT]

Hi Guys,

For an upcoming kit (Sport) what would be your choice in Motor Mount size, 29mm Or 38mm.

Kits Specs are:

22" 54mm Body Tube
5:1 Ogive NC Approx. 12" Long.
Approx. over all length 34"

 

[heada]

Always bigger so you can adapt down. I don't know of a way to adapt up.

 

[CoachSteve]

I like the 29/40-120 hobby line from Aerotech.
Reloads all the way up to a G76 and no Hazmat for most reloads
and $17 or less for each reload
I have a 4" by 5'6" scratch build that hits 900FT on a G76.
A 54MM rocket would be out of sight high in a real hurry on a G

 

[OverTheTop]

54mm

 

[CoachSteve]

hey - if you have level 3 cert and all the electronics and knowledge to track a rocket that hits 10K - go for it - a 54mm min diameter rocket is a sight to behold for sure

 

[GaryT]

I like the 29/40-120 hobby line from Aerotech.
Reloads all the way up to a G76 and no Hazmat for most reloads
and $17 or less for each reload
I have a 4" by 5'6" scratch build that hits 900FT on a G76.
A 54MM rocket would be out of sight high in a real hurry on a G

Agreed which is why I vote 29mm MM, this will be single deploy and light weight. However in this case its going to be majority rules.

 

[OverTheTop]

hey - if you have level 3 cert and all the electronics and knowledge to track a rocket that hits 10K - go for it - a 54mm min diameter rocket is a sight to behold for sure

54mm is the sweet spot for me, but a MD will go out of sight as you say. Tracking options are much cheaper and easier to find these days. Easy to use too.

 

[crossfire]

38

 

[FredA]

75mm -- easiest to pack and clean.
Makes K->M's which fit most flying fields.

 

[blackjack2564]

based on the kit specs 29mm is perfect for small motor deploy sport kit.

 

[mpitfield]

+1 You can easily go down but not up, and I am a fan of more flexibility, not less.

Always bigger so you can adapt down. I don't know of a way to adapt up.

 

[MushuTheGreatStoneDragon]

I think I'd have to agree with the 38mm and adapt it down philosophy. Especially if you may already have an adapter that will go from 38 to 29.

For now you may just want it as a simple kit that will pop the chute at apogee and float back down. But who knows, maybe you'll want to fit something bigger in it later and with things like the JL chute release and modern gps tracking hardware you can essentially do high altitude dual deploy like you would see in a rocket that's twice the size as what you've got. Toss a nice long reflective streamer on there for when it first opens up for even more chance of spotting a high altitude recovery.

Not to mention that (at lease from my perspective as of late) the price for reloads based off $/N-s for short and stubby motors seems to be more worth it than longer motors. i.e. a 1 or 2 grain 38mm reload will get you more impulse per dollar than a 4 or 5 grain 29mm. This applies more to the larger sizes of motors (like once you start thinking 75mm X 2 grain vs. 54mm X 6 grain), but to some degree this trend trickles down to the smaller sizes too.

Idk, my two cents. Ultimately up to you.

 

[Rocket501]

I have a special fondness for 38mm motors. Like the others have said, you can always adapt it down and I could imagine with a little reinforcement, the rocket would really rip on a J270.

Personally, I doubt the kit would be for me as I prefer 4” body tubes when I am not going minimum diameter, but I still think the majority of people would also like the 38mm mount.

 

[grouch]

Seeing how this is in the midpower section...29mm. The specs you posted seem ideal for a 29/240 case.

 

[BF Rockets]

98mm (sub minimum diameter)

 

[dpower]

29mm - If built from LOC tubing, I’ll guess no more than 1 lb, so it could fly from an E16 (~500’) to an I200 (~4000’).

 

[JohnCoker]

54mm

+1 this is a manageable size with lots of variety

 

[blackjack2564]

The choice for this kit is simply 29 or 38mm.
Why all the added larger sizes folks?
Gary is very specific for what this poll is for...trying to decide between the 2 nothing else.

 

[OverTheTop]

54mm airframe was mentioned, and the question was asked as to what OUR prefered size was.

I am guessing this is not the first time a thread has gone in a different direction than intended ,

 

[jadebox]

Always bigger so you can adapt down. I don't know of a way to adapt up.

I used a Forstner bit on a long shaft connected to a drill.

https://www.payloadbay.com/article-how-to-fit-a-54mm-motor-into-a-38mm-motor-mount.html

It worked in this case, but I highly recommend having the largest motor mount that fits for the reason stated above.

 

[mccordmw]

Judging by what I've launched the most, and looking at what I have in stock, I'd say the 38 is my favorite and most versatile. Most of my motor mounts are 54 mm, and I adapt down to 38 when desired.

 

[heada]

I used a Forstner bit on a long shaft connected to a drill.

https://www.payloadbay.com/article-how-to-fit-a-54mm-motor-into-a-38mm-motor-mount.html

It worked in this case, but I highly recommend having the largest motor mount that fits for the reason stated above.

That's not really adapting up so much as gutting the motor mount and rebuilding it.

 

[jadebox]

That's not really adapting up so much as gutting the motor mount and rebuilding it.

Well, yes.