mh9162013
Well-Known Member
When it comes to deciding what LPRs I should focus on and build, engine costs is the single most important driving factor. This is one reason why I try to focus on rocket designs and sizes that are 13mm BP engine capable, such as using an A10-3T or 1/2A3-2T. Even if it has an 18mm MMT, I'll want it to be able to fly with a 13mm engine and an adapter.
Generally speaking, the best price for these mini engines is about $2 each. But today, I was reading another thread here and discovered the Quest Q-Jet bulk packs. Yes, I've heard and seen them before, but didn't give them any serious consideration b/c they were more expensive than Estes 13mm engines.
For example, there's a 12 pack of Q-Jet A3-4s for less than $23. So now I'm reconsidering whether I should focus many of my rocket builds around the 13mm engine. Based on my research, here are the benefits of the Q-Jet A3-4s over an Estes BP rough quivalent, like the A8-3. These include:
- Price
- Cleaner burn (but is this actually true?)
- Quieter
Potential drawbacks of using a Q-Jet instead of an Estes BP:
- More finicky starting (not sure if this is true or just anecdotal)
- Might not fit in all BT-20 motor tubes due to slightly larger size (is this still true? And if it is true, some light sanding of the plastic casing should remedy this, right?)
- The ejection charge "thingy" sticking out on the top might not fit in some MMTs (probably not a major occurrence, though)
Here are my questions:
1. Am I missing any advantages or drawbacks of the Q-Jet over an Estes BP equivalent?
2. How does the ejection charge compare to the Estes BP 18mm engines? Specifically, isn't there some plastic cap that gets ejected into the rocket with the Q-Jet while the Estes BP 18mm engines just have tiny bits of clay to worry about?
Generally speaking, the best price for these mini engines is about $2 each. But today, I was reading another thread here and discovered the Quest Q-Jet bulk packs. Yes, I've heard and seen them before, but didn't give them any serious consideration b/c they were more expensive than Estes 13mm engines.
For example, there's a 12 pack of Q-Jet A3-4s for less than $23. So now I'm reconsidering whether I should focus many of my rocket builds around the 13mm engine. Based on my research, here are the benefits of the Q-Jet A3-4s over an Estes BP rough quivalent, like the A8-3. These include:
- Price
- Cleaner burn (but is this actually true?)
- Quieter
Potential drawbacks of using a Q-Jet instead of an Estes BP:
- More finicky starting (not sure if this is true or just anecdotal)
- Might not fit in all BT-20 motor tubes due to slightly larger size (is this still true? And if it is true, some light sanding of the plastic casing should remedy this, right?)
- The ejection charge "thingy" sticking out on the top might not fit in some MMTs (probably not a major occurrence, though)
Here are my questions:
1. Am I missing any advantages or drawbacks of the Q-Jet over an Estes BP equivalent?
2. How does the ejection charge compare to the Estes BP 18mm engines? Specifically, isn't there some plastic cap that gets ejected into the rocket with the Q-Jet while the Estes BP 18mm engines just have tiny bits of clay to worry about?