Am I the only one that does this?

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DeepOvertone

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I've been noticing a trend in myself and the rockets I'm interested in. I feel like every rocket I look at has too big of a motor mount. IE, when its a 54mm mount, I want to fly a 38mm motor. If its got a 38mm mount, I want to fly a 29mm motor in it... Not that the manufacturer made a poor design or anything but that more often than not, I dont want to put that much power into a rocket of that size.

Some of my reasons are:
Bigger motors are more expensive
Bigger motors of the same power move the CG further back
More powerful big motors launch it so high that I can't get any more enjoyment out of it past a certain altitude( I like being able to see most of the entire flight)
Higher altitudes have higher risk of losing it entirely.
And so on and so on....

Take my MC 3" Little John for example. It came with a 38mm mount. There is PLENTY of power in 29mm to get that rocket really going. My L1 with that rocket went to 2700 feet on a 29mm motor. And that was really pushing it for my tastes. I wont fly it that hard again.

Is it just me? Am I an old fart? LOL
 
No, I do the same thing. But having the larger mount opens the option of a bigger motor, should I choose to try one later.
 
Thats what motor adapters are for, I build most of my rockets with the largest motor I am likely to want to fly that way I have options. Example the AT pop/beer can motors (54/426) has some great motors, but the 38 and 29mm also have nice I class motors, its nice to be able to fly any of them in my rocket.
 
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I completely agree! - I thoroughly enjoy seeing the entire flight. I do a lot of low power for just those reasons (cheaper, can see it all, high likelihood of getting everything back)
I even fly low power multi-stage rockets on Bs just to see the deployments :).
Every now and then I send one way up, just to awe my audience (family) :)
I have a 5"6 x 4" build that I launch on 29mm G76s (nets about 800ft), its amazing to see and flies super straight and clean.
[video=youtube;YKWy6G59SmA]https://www.youtube.com/watch?v=YKWy6G59SmA[/video]
 
Thats what motor adapters are for, I build most of my rockets with the largest motor I am likely to want to fly that way I have options.

No, I do the same thing. But having the larger mount opens the option of a bigger motor, should I choose to try one later.

Yes. I forgot to mention that I do own all of the adapters I need to adapt to what I need. Also, if theres an option to buy one size or the other, I do always buy the larger mount just in case, while intending to adapt down. But I just found it odd that I pretty much always intend to adapt down from the main mount size.
 
I tend to do the same as well, adapting down. My Madcow Cowabunga flies more on 29mm motors than 38mm.
 
IMHO the bigger MMT's are the way to go and then adapt down if you want to, but most of the vendors will customize a kit with a bigger or smaller MMT if you call and ask them.
 
I like the idea of adapters... Low and Slow can be fun, but when the chance to open up and "Let'r Rip!!!" comes up it's nice to have that option too.

Then again... Vendors would probably appreciate it if you'd just do the honest thing and buy and build one of each. :wink:
 
When I started getting into HPR, I was always wondering why the heck didn't Madcow make the Cowabunga or Big Fizz in 29mm, and similar thoughts with LOC. Why would I want a 38mm hole? Then I actually started flying HPR and I was thinking "Okay, I see now". Then "The Tembo would fly great on soda can motors" so out went the 38mm and in went the 54mm. Maiden flight Saturday BTW.

I would like to see my level 1 bird fly on the soda cans as well, but alas it is 38mm. I was advised to build it with the 54mm but the 54MMT in a 2.6" rocket was a bit more than I felt comfortable working with at that time. Still pleased with the rocket though and I really need to fly the darn thing again. Nice to not have to adapt down to fly it as well.

And the Little John, well it loves Loki 38/120s and they just don't fit in a 29MMT. Adapting down, it will probably fly really well on the 29/180 loads, may be a good sweet spot. I'll have to try that. Yours went 2700 feet on your level 1 flight? And you were able to keep your eye on it? I ask because I plan to fly mine Saturday on my H73J and it sims to 2100, shouldn't be too hard to spot.

Aerotech 38mm cases are actually cheaper than their 29mm counterparts.
 
Sounds like you are running into the "fly the field" issues that most of us cope with as we advance through the levels. You build a rocket that has an "appropriate" sized MMT and then find that it works pretty well on smaller motors most of the time.

There is nothing wrong with adapting down, for any reason! I usually adapt down because of weather conditions, i.e. wind levels. At the same time I may fly a 38/240 instead of a 38/600 case. I consider that adapting down also. It's all about "flying the field".

The higher your cert level, the more that comes into play. Don't worry about it, just fly what you think you need in each rocket.
 
One thing to consider is ... since most of our motors are core-burners, a larger diameter allows for a longer-burning motor, not necessarily a higher-thrust one. I once built a draggy rocket with a 38mm mount and had to modify it to allow a 54mm motor after I realized that 38mm motors weren't right for it. A larger diameter mount really opens up a lot more choices for motors within the same total impulse range.
 
My general rule is that I want to be able to fly a rocket on the smallest motors in that diameter, or close to it. So if I put a 29mm mount in, I want to have at least one F that works.

That said, I like both low-and-slow and screamers, so adapters are a good option. However, I tend to do more building than flying, so I have a few slow rockets and a few fast ones, and don't usually overlap them too much.
 
I think the same way, I tend to scratch build with a size smaller motor mount than most people. One of my first scratch built HPR creations is a seven pound 4" rocket with eight fins and a bulging canopy. It has a 29mm mount and flies great on an I200.

IMG_3432.jpg

IMG_2437.jpg
 
That's super cool. I don't think people appreciate the 29mm enough. Seems people quickly want 38mm and up shortly after obtaining their L1. I think H's and I's in 29mm are way more interesting that the same impulse in 38's. The next Minnie Magg I build will be with a 29mm mount in it because I think it would be interesting to load 6 grain motors in it.
 
I've been noticing a trend in myself and the rockets I'm interested in. I feel like every rocket I look at has too big of a motor mount. IE, when its a 54mm mount, I want to fly a 38mm motor. If its got a 38mm mount, I want to fly a 29mm motor in it... Not that the manufacturer made a poor design or anything but that more often than not, I dont want to put that much power into a rocket of that size.

Some of my reasons are:
Bigger motors are more expensive
Bigger motors of the same power move the CG further back
More powerful big motors launch it so high that I can't get any more enjoyment out of it past a certain altitude( I like being able to see most of the entire flight)
Higher altitudes have higher risk of losing it entirely.
And so on and so on....

Take my MC 3" Little John for example. It came with a 38mm mount. There is PLENTY of power in 29mm to get that rocket really going. My L1 with that rocket went to 2700 feet on a 29mm motor. And that was really pushing it for my tastes. I wont fly it that hard again.

Is it just me? Am I an old fart? LOL

Yes, you're an old fart! :wink:

I know I'm right because it takes one to know one!

I still build with the larger MMTs but I get plenty of use out of my adapters.

I used to always try to fly the largest motor, but being an old fart, I don't like the long walks as much anymore, so I fly the field and wind conditions more conservatively than I used to. The one thing that has pushed me back to using the larger motors again is the JLCR. I tend to use 200 ft as the release point because it means less walking.
 
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