29mm HPR or 38mm HPR

[BrianURocket]

So, I'm gonna go for my L1 after a winter build. Been looking at HPR motors, casings, reloads, etc. Upon discovering 29mm and 38mm, running some RockSims, etc. Wondering if anyone has an opinion on 29mm vs. 38mm. I'm building with a 38mm mount, but appears a 29mm H180 will actually work better for my L1 flight than a 38mm H123. Plus, I can use the 29mm hardware in some of my MidPower birds. The only reason I'm asking is because I recall reading somewhere (and can't find it) that the 29mm HPR wont' "work" as "well" as the 38mm HPR? I know one is smaller dia and longer, but isn't a motor specification, simply that, a motor specification and if that specification is the best or works, it should perform. Agree?

 

[atxcple]

oh treading narrow edge when asking opinions on TRF:wink:

Here is my OPINION which will differ from some and not others.

29 Vs. 38 i fly both most HPR rockets in my collection can. 38mm mounts 29mm adapters...with CTI starter sets priced the way they are get both. this is comming from someone who has pro29 cases from 1 grain to 6 grain. Pro38 3 grain to 6 grain. AT 29/100, 29/180, 29/240 AT 38/240 thru 38/720. certing on 29mm is what i did for L1. 38mm for L2. i recommend building in 38mm w/29mm adapters which gives you a lot more choices for motor selection, colors, velocity, altitude. most depends on what your goal is for your rocketry experiance. i fly 50/50 29mm vs. 38mm all depends on what im looking for some of my 29mm motors out perform the 38mm's. i mean have you heard a 6 grain 29mm skidmark? HOLLY COW BATMAN

 

[english_1969]

Speaking from experience and regret, I would have chosen a 38mm setup for my L1 instead of the 29mm I chose.

Why? Well, soon after getting my L1, I was ready to fly larger motors. Unfortunately, the rocket I used was already topped out with the largest 29mm. It could have easily handled a larger 38mm.

I made the same mistake with my L2, i used a 38mm instead of 54mm. Same thing, the rocket I used could have been really fun to fly on a larger 54mm motor instead of being strapped with a 38mm.

And, by the way, fellow board members told me to size up and I didn't listen.

Just my $0.02.

W

 

[DAllen]

Not completely sure what you are getting at...BUT I do think you made the right call building it with a 38mm mount rather than a 29mm because as you probably already know, you can always adapt down and not up. As far as 38 performing better than 29 - I've never heard of such a thing. Why would the H180 work better than the H123 anyways?

https://www.thrustcurve.org/motorsearch.jsp?id=139

https://www.thrustcurve.org/motorsearch.jsp?id=128

 

[Wingarcher]

There's two questions here, I think.

Should I build this rocket with a 29 or 38? Is it a Loc Weasel? Definitely go with the 29. Is it a 3" fiberglass dual deploy capable rocket? 38 (or maybe 54 and fly with a 38 adapter, depending on your flying field). Have to decide that rocket by rocket.

As for the motor choices- an H is an H, but a 38mm H will be shorter than a 29mm H. The 29mm motors are less expensive than the 38. But you're limited to a small I in 29mm. If you plan to build smaller rockets the 29mm is plenty. If you plan to fly big stuff (and want to spend that kind of $), plan to build bigger rockets and go with bigger cases. I'm an L2 and lately I've been regressing to small dual deploy rockets with 29mm mounts. It's cheap fun. DD with a raven, 2300ft on a G64. Same rocket will go the altitude a large rocket (3" Talon) needs a J350 for... on a medium H for half the cash.

Aerotech 29mm HPR is a killer deal, especially with the discounts some dealers offer. Only the black jack motors in that line require HAZMAT shipping!! US mail for the rest- you can buy two motors if you want and not get killed on shipping! Smaller range of choices than CTI and assembly required- but if you want altitude on the cheap....

N

N

 

[ggoldy]

So, I'm gonna go for my L1 after a winter build. Been looking at HPR motors, casings, reloads, etc. Upon discovering 29mm and 38mm, running some RockSims, etc. Wondering if anyone has an opinion on 29mm vs. 38mm. I'm building with a 38mm mount, but appears a 29mm H180 will actually work better for my L1 flight than a 38mm H123. Plus, I can use the 29mm hardware in some of my MidPower birds. The only reason I'm asking is because I recall reading somewhere (and can't find it) that the 29mm HPR wont' "work" as "well" as the 38mm HPR? I know one is smaller dia and longer, but isn't a motor specification, simply that, a motor specification and if that specification is the best or works, it should perform. Agree?

Go for "low, quick, and safe." Get your cert out of the way..... then 'play'.

GGoldy

 

[BrianURocket]

Thanks for the opinions. Confirms my thinking. I'm building with 38mm Mount. I may L1 cert with 29mm, will get me approx 1000ft for a safe cert flight. Then I'll be able to use the hardware on some of my 29mm MPR immediately. Plus, I can even do an I in the 29mm if I get the case. Future, maybe even later next year, I can get the 38mm hardware. I guess my real question was "is it worth getting the 29mm HPR or just jump to 38mm?" Based on my sims and my plans in MPR and the opinions here, it confirms I should get the 29mm HPR, then the 38mm later. I'll probably get more use out of the 29mm HPR hardware.

 

[Golfpro62]

Everybody so far is right in one way or another. You will immediately after your level 1 want bigger and badder motors and 38mm can offer some pretty big J motors (J570 or J825) they are both really cool motors and pushing a 1000 Ns. Trust me - once you launch one of those your going to want 54mm and then you'll want to go ahead and try for level 3, it's like a addiction. For most of us though, money will become an issue - your talking some serious cash once you start flying 54mm and bigger. Somebody earlier talked about going backwards a little bit flying smaller birds with 29mm - funny that I have started to do the same thing, it's still very cool and heck - you can pick up a 29mm H motor for $15. The Pro-X cases with the spacers offer you the ability to go both 38 and 29 without breaking the bank. Im strictly an Aerotech guy but only because thats what was available when I got started. If I could do it over again - no question Pro-X is the way to go and the bonus is they are simple to assemble.

 

[bjphoenix]

I did my L1 about 10 years ago and I used 38mm. I have built a couple of LOC kits using 38mm mounts, and it seemed to me that 38mm would be more versatile. I bought the 38/240 and 38/480 so I could fly with H and I. I already had the 29/40-120 casing for my lower impulse flights.

I believe one of my LOC kits came with a 29mm-38mm adapter, which is a pretty simple thing actually, so even if you build with 38mm mounts it is easy to adapt to 29mm.