Level 1 with Leviathan

Ok, some guys in the club are encouraging bad behavior. They are telling me I should go for my L1 this coming summer, using my Estes Leviathan.

I built my Leviathan mostly stock, but I made a few changes:

1. Left out the motor block
2. Yellow wood glue for wood parts, internal fillets on fins and centering rings
3. Eyebolt in top centering ring, reinforced with JB Weld
4. Loop of braided Kevlar through eyebolt, tied to shock cord, quick link at end of shock cord for parachute and nose cone
5. Both Lugs and Railbuttons

I've flown it on F motors, and it flies fine, but I'd like to stretch it a bit.

The club flies at a sod farm, so lots of space, soft grass for landing. The general advice is to use an H155DM and drill the delay, and use a chute release if I so wish. I've simmed it in OR, and it seems like it will go to about 2300 feet or so, with about a 9 second delay. Does that seem reasonable?

I've done a search on the forum, and it seems several people have done an L1 flight with a Leviathan. A couple mention a vent hole, though. Is that necessary for this altitude?

Many people have done L1 on Leviathans built the same as yours, go for it....

I did my L1 on a Leviathan. Wood glue, rail buttons and Estes 29mm retainer. I used the coupler to make an AV bay but flew motor deploy with H128 for cert flight. No vent holes.

Yup, great kit for L1, I did many similar mods and mine is 3 tube... only 1859 feet on the H165R, I'd assume 2200-2300 is about right for a two tube. 9 second delay on mine too, popped right at the top.

gna said:

I've done a search on the forum, and it seems several people have done an L1 flight with a Leviathan. A couple mention a vent hole, though. Is that necessary for this altitude?

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That's an interesting question, but its hard to answer. Back of the envelope, assuming a launch from near seal level, further assuming a tightly fitted nose-cone with little leak-by; the pressure difference across the airframe at apogee would be about 8 kPa. So figure a force of about 40 Newtons (about 8 lbs) acting to separate the nose-cone. Cost-Benefit; the vent hole won't hurt the performance of the rocket and might save you from a premature separation and failed recovery on your cert attempt.

Go for it. If you've flown Mid-Power with success, L1 is easy.

I have the original 4 Pro Series II rockets setup with electronics and fly them on H's (should give them an I, by further anecdata, ive overbuilt them)

I did my L1 on a Leviathan that was closer to stock than yours. No problem. I have vent holes....but they are for an altimeter. I like to fly altimeters in as many of my flights as I can. I don't use them (yet) for deployment, just data gathering.

As you can see from the graph, in my case 9 seconds was a bit long.

(Gee, it doesn't seem like that was over 7 years ago....).

jlabrasca said:

That's an interesting question, but its hard to answer. Back of the envelope, assuming a launch from near seal level, further assuming a tightly fitted nose-cone with little leak-by; the pressure difference across the airframe at apogee would be about 8 kPa. So figure a force of about 40 Newtons (about 8 lbs) acting to separate the nose-cone. Cost-Benefit; the vent hole won't hurt the performance of the rocket and might save you from a premature separation and failed recovery on your cert attempt.

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May as well do it, then. I figure a 1/16" drill should be fine...

BEC said:

View attachment 402970 I did my L1 on a Leviathan that was closer to stock than yours. No problem. I have vent holes....but they are for an altimeter. I like to fly altimeters in as many of my flights as I can. I don't use them (yet) for deployment, just data gathering.

As you can see from the graph, in my case 9 seconds was a bit long.

(Gee, it doesn't seem like that was over 7 years ago....).

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OR tends to be a bit optimistic. I ran the same sim several times, and I get 8.5 secs to 9.1. I think the delay drill is in two second intervals, so I suppose I'll go to 8 seconds and call it good.

gna said:

OR tends to be a bit optimistic. I ran the same sim several times, and I get 8.5 secs to 9.1. I think the delay drill is in two second intervals, so I suppose I'll go to 8 seconds and call it good.

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That's not a sim. That's data from a PerfectFlite Pnut aboard the Leviathan on that flight.

You could always borrow a casing and run an h97, soft and smokey.

Did my L1 on a Leviathan. Added 34" of BMS BT300 tube and called it "stretch". Chore boy baffle in the coupler. H128 pop at the top. Landed 50' from pad.

All wood glue construction (except JB weld for retainer). Internal and external fillets (TBII).

Flown subsequently on H165R, H180W, H210R and I200W all with no damage.

I'd say put the biggest bang you have in it and go for it!

BEC said:

That's not a sim. That's data from a PerfectFlite Pnut aboard the Leviathan on that flight.

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Yes, I realize that. Sorry, I was not clear.
I was commenting that OR tends to be optimistic and that 9 second delay may be too long, as your data demonstrates.

Ah, sorry. I realized after I posted that you could have meant that, as well.

That H155 has a little more total impulse than the H87 I used but since it’s higher thrust it’s also higher drag (which goes up with the square of velocity). That said, you might get going enough faster that a 9s coast time is plausible at least.

I've flown mine on a few small H motors. No issues. Just remember to ensure it balances properly! (I did add some nose weight to mine once I decided to allow it on H's)

I will throw in my "Go for it" vote.

I'll take a different view. Ask yourself why you want a Level 1 certification? The H-I impulse levels opens you up to higher, faster, bigger, more payload, etc. Your Estes MPR rocket will quickly become insufficient for exploiting these benefits. I say build a new HPR rocket for HPR motors and HPR objectives. You always need more rockets!

Buckeye said:

... You always need more rockets!

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Alternately, if storage space is tight, loading it with an I205 will likely open up a spot on the shelf for the next rocket. >smile<

Buckeye said:

I'll take a different view. Ask yourself why you want a Level 1 certification?

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It's just something to do...not a commitment or a promise to fly more H motors. High power is expensive, and for some of us occasionally sticking an H motor in a capable mid power rockets is enough.

astronwolf said:

It's just something to do...not a commitment or a promise to fly more H motors. High power is expensive, and for some of us occasionally sticking an H motor in a capable mid power rockets is enough.

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Very well said.

astronwolf said:

High power is expensive, and for some of us occasionally sticking an H motor in a capable mid power rockets is enough.

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That's me as well, I fly my 24/40 reload LOTS, occasionally a "G", and a few Hs (and once an "I").

My 2 cents: I did My L1 Cert with a Upscaled MARS LANDER at 1.6X on an H97. Yeah, Everyone thought I was Insane. But it was a perfect flight. As I replied to the RSO questioning if I really wanted to try that: If you cant run with the big dogs, Stay home on the porch. He put me on Pad #13. Best Flight of my Life right there. Then again, I suspect I was hovering about 3" off the grass I was so excited. Thus my comment: GO FOR IT.
Now, I have used the 3D CAD at work to do my next bird. A 3X Mars Lander. Yes, I'm going for my L2 with it. And NO, there is no Plywood in it. Engineering replaces heavy plywood with designed structure of less weight and more strength.

Thanks for the advice, everyone. I've decided to go for it this summer. I'll fly it on G motors a couple of times first.

Buckeye said:

I'll take a different view. Ask yourself why you want a Level 1 certification? The H-I impulse levels opens you up to higher, faster, bigger, more payload, etc. Your Estes MPR rocket will quickly become insufficient for exploiting these benefits. I say build a new HPR rocket for HPR motors and HPR objectives. You always need more rockets!

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Well, I was just talking about stretching it out on G motors, and the bad influences encouraged me to go for the Level 1...

astronwolf said:

It's just something to do...not a commitment or a promise to fly more H motors. High power is expensive, and for some of us occasionally sticking an H motor in a capable mid power rockets is enough.

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Well said.

mbeels said:

That's me as well, I fly my 24/40 reload LOTS, occasionally a "G", and a few Hs (and once an "I").

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I think that's the way I'll go, too.

Yes, go for it.

https://www.rocketryforum.com/index.php?posts/1707381/

My wife and I were cleaning the office this weekend, and I pulled out my unflown Leviathan. I modified it for conventional dual deploy, with anti zipper baffle. Av bay right in the middle. I had to order an extra coupler from Estes during the build phase but it worked out as I had some other stuff that I ordered from Estes. I hem and haw about if I should just fly it or give it away. I built the av bay sled to use the Adept22 altimeter which I am running out of... My Adept22's are modified with LED's in place of the Piezo so I can see the status of the altimeter.

Perhaps I should just get it done. At least I'd have something "fun" to fly at launches on 29mm motors, which I have a crapload of...

mrwalsh85 said:

I built the av bay sled to use the Adept22 altimeter which I am running out of

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Borrow one from a different rocket?