which motors to use with these mpr rockets?

Greetings from Europe!

Please excuse my bad English - it's a foreign language to me
My model rocket experience so far: a few starts with c motors

I want to start building and fly mpr rockets now. The two rockets kits I want to start my mpr experience with are:

* bullpup from qmodeling
https://www.qmodeling.com/QModeling/Prod-Rocket-Bullpup.htm
Comes with a 24mm motor mount
* cheetah from aerotech
https://www.aerotech-rocketry.com/
Comes with 29mm motor mount with included 24mm adapter

In case if you want to reply on my questions, keep in mind, that:
I want to use a similar or maybe the same motor type with both rockets – so I can exchange them.
I want to use a wide variety of motors.
I want to use a relatively cheap solution.
I use a 1.5m (or maybe 2m) long rail to launch my rockets from ( https://www.raketenmodellbau.org/forum?action=viewthread&threadid=4996&page=4 )

Here are my questions:
1) Would you recommend rms or single use motors for these rockets?
2) Should I consider using 29mm motors with these rockets, although the bullpup recommends 24mm?
3) Which motor types do you recommend for save and easy first launches with the bullpup?
4) Which motor types do you recommend for save and easy first launches with the cheetah?

Whoever takes the time to read and answer my post: thanks in advice!!!

although I have neither rocket, it would seem to me that if you want to use single use motors in both, the: E15, E30, F20-7, and F23-7 would all be decent 24mm choices for both rockets. If you want to spend money on a reloadable motor case, you could fly either on a D15-4, E18-7, E28-7, F24-7 or F39-7 with good results. You may want to use slightly shorter delays with the bullpup, although you shouldn't have to make much adjustment if you build light (and strong)

Oh, and about your English (written at least)... it's better than some of people who post on here, from the US or UK! BTW, where are you from? (country/region?)

For the most part, 24mm motors that are offered often have as much thrust as some 29mm [compare 24mm E's and F's to 29mm E's and F's ] (except when you get into G's, then you have to go to 29mm)

Hope this helps, and I'm sure others will chime in with their advice and experience. Welcome to TRF

Go back to the areo-tech web site, under resources, click the catalog, on the pg. with the cheeta it shows all the recommended engine combos.

i come from austria - central europe:
Longitude: 15.592
Latitude: 48.4084

AT Cheetah you can fly on
Estes D12-3's and E9-4's
on a small field if you don't
build it overly heavy....

I've got dozens of good flights
with both on my AT Mustang,
thats a Cheetah with one more fin.

Originally posted by skyfox
1) Would you recommend rms or single use motors for these rockets?

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That mostly depends on how much you pay for reloads compared to single-use, and how often you will use it. The RMS system has a higher starting cost because of the expensive casing, but the fuel is cheaper. Here in the US, the difference in fuel price make RMS cheaper after about 5 flights with 29mm motors. For 24mm motors, more flights are required to make up for the additional cost of the casing.

Something else to consider is the convenience. With single-use you can prep a rocket much quicker than assembling an RMS motor. With single-use there is no cleanup after a flight and no waiting for the motor to cool down between flights.

When flying to high altitudes or in harsh conditions, there is also the risk of losing your expensive casing.

I use mostly Estes D12 and E9 engines for my 24mm models. I sometimes use single-use Aerotech engines if I have traveled to a large flying field. I will probably invest in RMS when I move up to 29mm.

2) Should I consider using 29mm motors with these rockets, although the bullpup recommends 24mm?

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I recently finished building a QModeling Bullpup. It is a beautiful rocket and the construction details are outstanding.

All QModeling kits are designed for 24mm motors. Because of the way the motor mount / fin cage is constructed, it would be extremely difficult to modify them for use with 29mm motors.

3) Which motor types do you recommend for save and easy first launches with the bullpup?

Click to expand...

An E9-4 worked well on my first Bullpup flight. Liftoff was a little slow but it kept accelerating a long time. I would not recommend the E9 in windy conditions, though, since it does not have enough early thrust. An E30-4 would be an excellent choice. F21-6 would be good also, as long as you have a large enough field.

thanks for your answer, bob!

i think your idea is a good one - i am new to rockets and single use engines would be easy and fast to start with. when i like this hobby and continue flying, i can easily switch to 29mm reloads, cause the aerotech cheetah would work perfectly with them.

read somewhere else, that a lot of people fly the bullpup on the e9-4 engines, so i will give them a try for the first time and then i will add more power, as you recommended.