Esam 58 with 24mm mount

[TheBob]

I'm going to start a build on Hobby lobby Estes Esam 58
attached is an ork file
Moved the forward fins back to 2" (from 3")
Fins are in line and not offset 45°
Motor mount tube is 7" with three centering rings.
IIRC stability is between 1.71 and 1.15 (C11 to E12)
any opinions?

 

[bjphoenix]

I think you have to be brave to launch one on an E, but I feel the same way about other E designs like the Cherokee E and the Hi-FlierXL. However I did see a HiFlier XL launched on an E and it was recovered.
I have an ESAM 85 and fly it on B engines on real small fields, and C engines on larger fields. The HiFlier XL is not really all that much larger than the ESAM but just enough that it really needs a D if you want a reasonable flight. So I think your ESAM would work well on a D, if you really want to use E engines you might have to adjust the fins a little bit more or add a bit of nose weight.

 

[smstachwick]

I think you have to be brave to launch one on an E, but I feel the same way about other E designs like the Cherokee E and the Hi-FlierXL. However I did see a HiFlier XL launched on an E and it was recovered.
I have an ESAM 85 and fly it on B engines on real small fields, and C engines on larger fields. The HiFlier XL is not really all that much larger than the ESAM but just enough that it really needs a D if you want a reasonable flight. So I think your ESAM would work well on a D, if you really want to use E engines you might have to adjust the fins a little bit more or add a bit of nose weight.

I’ve flown my Hi-Flier XL on E motors several times. At LDRS I even put a booster on it and sent it on an E12-0/E12-8 stack. Both pieces recovered, although I’m going to make some adjustments before flying that configuration again.

Estes E motors burn for a longer time and produce relatively low thrust, meaning that they need a pretty light airframe to lift off safely and will inevitably go pretty high. A heavier rocket can take something like one of the new Q-Jet E35Ws and stay lower.

That said, I think the OP would be smart to start on the 18mm motors it was originally designed for. Build it with the 24mm mount and adapt down, start on a B4. The packaging recommends a -4, my OR simulation says it’s closer to a -2.

(Actually my simulations say an A8-3 will deploy safely, although apogee is under 100 ft.)

Fly the field, see what kind of impulse you can install and still consistently achieve safe, on-field recovery. If you get to the C range, you’re ready for 24mm (although there are some neat C and D options in 18mm).

After that you’re leaving the LPR realm for MPR. You can really get crazy with even the 24mm motors in that range, so I’ll just leave my recommendation there. You’ve got plenty to explore up to D power.

 

[bjphoenix]

(Actually my simulations say an A8-3 will deploy safely, although apogee is under 100 ft.)

That's interesting, mine on a B6 doesn't fly very high so I'll stick with that as the minimum. If a person likes high altitude they can always build with 24mm and then adapt down to 18mm for a B on a small field.

 

[Back_at_it]

The ESAM flies really well on a C11-5. I too built mine with a 24mm mount but It has flown on B4-2, B6-4 and C6-3 motors. I personally wouldn't fly on a B6-4 again as I had a late ejection.

For small fields the B4-2 is just about perfect.

 

[TheBob]

The ESAM flies really well on a C11-5. I too built mine with a 24mm mount but It has flown on B4-2, B6-4 and C6-3 motors. I personally wouldn't fly on a B6-4 again as I had a late ejection.

For small fields the B4-2 is just about perfect.

The field that I use is about 350 yards x 450 yards.
I am did use a "E" length mount but I will mostly fly it with C to D with a 1" spacer. The fins are inline and the forward fins are move to 1 3/4" insead of 3"

 

[smstachwick]

The field that I use is about 350 yards x 450 yards.
I am did use a "E" length mount but I will mostly fly it with C to D with a 1" spacer. The fins are inline and the forward fins are move to 1 3/4" insead of 3"

The NAR Safety Code does allow launches of G motors in fields of this size. I wouldn’t want to do that in this rocket unless it was dead calm, though. Recovering from over 1000 ft can be a challenge on fields of this size, I think limiting yourself to E power at this field would be smart.

 

[bjphoenix]

The NAR Safety Code does allow launches of G motors in fields of this size. I wouldn’t want to do that in this rocket unless it was dead calm, though. Recovering from over 1000 ft can be a challenge on fields of this size, I think limiting yourself to E power at this field would be smart.

The first flight of my ESAM on D12-7 was on a calm day and it came down about 25' from the pad. The second flight, relatively calm conditions, it bent a little off the rod and may have been 150 yards away. I launched a similar size rocket last weekend on a D12-5 and it landed about 100 yards away. You might have good luck on a 350x450 yard field, but with E motors there is a small chance of failure.

 

[TheBob]

Motor mount/stuffer tube. Forward centering ring is not on it in this pic.. I will be better about taking pics as I build this..
I have never used/built a baffle. How much space is needed/recommended in the upper portion of the body tube for the shock cord/parachute? I guess what I am asking is if I use a baffle how far down the body tube should I put it?

 

[smstachwick]

View attachment 532797
Motor mount/stuffer tube. Forward centering ring is not on it in this pic.. I will be better about taking pics as I build this..
I have never used/built a baffle. How much space is needed/recommended in the upper portion of the body tube for the shock cord/parachute? I guess what I am asking is if I use a baffle how far down the body tube should I put it?

I like to fold my parachute down into thirds, but since I’m folding the radius into thirds, the packed length ends up being about one-sixth of the diameter. So with a 12-inch chute, it ends up being about 2 inches long. Leaving about that same amount of space for the shock cord works out to about 4 inches from the top.

You could always cut it out and reinstall if that ends up not being enough.

 

[Back_at_it]

View attachment 532797
Motor mount/stuffer tube. Forward centering ring is not on it in this pic.. I will be better about taking pics as I build this..
I have never used/built a baffle. How much space is needed/recommended in the upper portion of the body tube for the shock cord/parachute? I guess what I am asking is if I use a baffle how far down the body tube should I put it?

I generally leave 5 to 6 inches on a rocket this size. You don't want to force the parachute in there and you need to consider the length of your shock cord as well. I tend to make them longer that normal so I fact that in. Also remember to leave room for the shoulder of the nosecone.

 

[bjphoenix]

I guess what I am asking is if I use a baffle how far down the body tube should I put it?

The ESAM isn't overly long, I think I would shorten the motor tube to hold a D or E whichever you prefer and that would leave room for the baffle and plenty of room for the parachute. Baffle designs can vary but I think you can build one within a length of 1 to 1.5 times the diameter of the airframe.