Flying Estes Maniac, kit 2091, on an E9-4?

[brockrwood]

I found a 1990's era Estes "Maniac" rocket kit in my collection and I decided to build it. It is rocket kit 2091. Even the instructions are yellowed! It's vintage!







Anyway, the instructions say to fly the model on a D12-5, D12-7, E15-6, or E15-8.

I want to fly it on "E" engines. The problem: The only "E" engines I have are "E9-4" engines. These are vintage, too!

See pic.



I downloaded the Rocksim file for this rocket and simulated it flying on an E9-4 in OpenRocket. (Rocksim file from rocketreviews.com.)

The sim says that the velocity off the rod is 41.5 feet per second and the apogee altitude is 1,182 feet. The "optimum" ejection delay is 6.67 seconds (so the 4 second delay is a little soon for the ejection). The velocity at deployment is 89.4 feet per second!

So, what do you wise rocketeers think? Can I safely fly the Maniac on an E9-4? The speed off the rod is a bit low but I have a 4 feet long rod. The speed at deployment scares me.

I cannot find the Estes E15-6 and E15-8 engines on Estes' website. Are they not made anymore?

Should I just fly it on D12-5's and D12-7's? Bummer! I wanted to try my first "E" powered rocket. It would make me an official "mid-power" rocketeer!

The altitude of 1,182 feet seems really high. I can't imagine it will really get to that altitude. Will it?

(Oh, does anyone want a PDF or JPG of the instructions, card, or decals?)

Any advice?

 

[heada]

Swap the E9 for an E12. The E9 is known for high failure rates and the E12 is the replacement.

The added weight of the E9/E12 vs the initial thrust may be too little thrust to get stable off the rod.

I would use an Aerotech reload in either the 24/40 case or the 24/60 case.

 

[brockrwood]

Swap the E9 for an E12. The E9 is known for high failure rates and the E12 is the replacement.

The added weight of the E9/E12 vs the initial thrust may be too little thrust to get stable off the rod.

I would use an Aerotech reload in either the 24/40 case or the 24/60 case.

Thanks for the advice.

I re-ran the simulation with a 6 feet long launch rod. The velocity off the rod is still only 47.7 feet per second. Not super-slow, but definitely on the low end.

On the plus side, the stability margin for this rocket, according to the simulation, is 1.89 caliber. That is fairly stable. Gosh. I would like to use these engines, but they seem marginal for this rocket. I guess there was a reason Estes recommended the higher average thrust engines for this rocket.

 

[trialsguy]

I also have a ‘yet to be built’ Maniac and some E9 motors. I’m wondering what the failure rate is of the Estes E9’s? Is it 1% , 10%, 50%? Or?

If it’s closer to 1%, I think I’ll risk it .

-Dave

 

[heada]

For the record, the E18 is an Aerotech reload. 3pack for about $32 plus the case for about $60. The case is cleaned and reused. In that same case is an E28, F24 and F39 that would work too. Aerotech makes single use 24mm F30 and F32. They also have an Enerjet set in 24mm as the E20, E30 and F44. Lastly is the Quest line with has the D22 and E26.

24mm wide by 70mm long (D12 size) has lots of options if you look beyond Estes.

 

[heada]

You'll never get a true failure rate but from my personal experience its between 10% and 25% Lots of factors include storage and handling as well as some lots are more prone to failure than others.

 

[brockrwood]

For the record, the E18 is an Aerotech reload. 3pack for about $32 plus the case for about $60. The case is cleaned and reused. In that same case is an E28, F24 and F39 that would work too. Aerotech makes single use 24mm F30 and F32. They also have an Enerjet set in 24mm as the E20, E30 and F44. Lastly is the Quest line with has the D22 and E26.

24mm wide by 70mm long (D12 size) has lots of options if you look beyond Estes.

Dang, I wonder what rocket I bought these E9-4's for? I will have to google rockets that fly on E9-4's.

 

[flaperon]

That rocket looks like it was designed by the writers of "Saved by the Bell"! It could well have been called the "Extreme" as everything else was back then

Good luck on the flight.

 

[heada]

E9/E12 is good in lightweight rockets or clusters. Estes Hi-Flyer XL is a good option for lightweight but still cheap enough to risk it having a failure. I have an old USRockets AeroRoc-3 that has a 3x 24mm cluster mount that flew great on 3x E9-6 and now I use 3x E12-6

 

[brockrwood]

Hmm. I just flipped through the 2004 Estes catalog at the Estes website. The catalog says the V-2 and the Executioner rockets fly on E9-4's. Don't see any other rockets that do. I have an old Executioner but I have not built it yet. Guess I will have to if I want to use the E9-4's.

 

[brockrwood]

Hmm. I just flipped through the 2004 Estes catalog at the Estes website. The catalog says the V-2 and the Executioner rockets fly on E9-4's. Don't see any other rockets that do. I have an old Executioner but I have not built it yet. Guess I will have to if I want to use the E9-4's.

 

[kuririn]

The short lived E-15 motors were a bit shorter than the newer E9 and 12s.
Likewise the engine hook, so that E9 motor might stick out a bit.
Just stick an AT E-30 in there and let er rip.

 

[kuririn]

PS forgot to mention if your delay is substantially shorter than optimal you stand a good chance of zippering the tube or damaging the recovery laundry..

 

[Initiator001]

Note that the stock Maniac kit cannot handle high-thrust motors.

I modified one to fly on an 29mm F62-9 DarkStar motor and the rocket came apart under thrust.

 

[kuririn]

Ergo the expression "let er rip".

 

[brockrwood]

The short lived E-15 motors were a bit shorter than the newer E9 and 12s.
Likewise the engine hook, so that E9 motor might stick out a bit.
Just stick an AT E-30 in there and let er rip.

So the engine hook is gonna’ be not quite long enough to hold an E9 in? Chit!

 

[brockrwood]

So the engine hook is gonna’ be not quite long enough to hold an E9 in? Chit!

Rats! E9-4 is 95mm long. The E15’s are 89mm long. Guess I will have to “unbend” the engine hook. Or just fly it on D12’s. Sigh.

 

[Rocketjunkie]

I've built Maniacs (later Eliminator) with 29 mm mounts. They are stable even without nose weight on a G25 or G40. The old DMS G25 was the perfect motor (along with the Ellis G20). With a G, they can become dynamically unstable in a strong cross wind. Any higher thrust and they will shred. It will be stable on any 24 mm motor you choose to install.
E15's were Estes first attempt at an E motor. They became bombs after being in the supply chain for a couple years.

 

[kuririn]

Rats! E9-4 is 95mm long. The E15’s are 89mm long. Guess I will have to “unbend” the engine hook. Or just fly it on D12’s. Sigh.

Check out Option 2 on page 5 of this Apogee newsletter article.
Good information in there.
Newsletter415.pdf (apogeerockets.com)

 

[brockrwood]

They became bombs after being in the supply chain for a couple years.

!!

 

[brockrwood]

Check out Option 2 on page 5 of this Apogee newsletter article.
Good information in there.
Newsletter415.pdf (apogeerockets.com)

Per the article, it looks like I can just let the E9-4 motor stick out a bit but wrap the end of the motor and the clip with masking tape to make sure the engine does not “rear eject” itself.

 

[brockrwood]

Swap the E9 for an E12. The E9 is known for high failure rates and the E12 is the replacement.

The added weight of the E9/E12 vs the initial thrust may be too little thrust to get stable off the rod.

I would use an Aerotech reload in either the 24/40 case or the 24/60 case.

I am definitely leaning towards just getting some E12’s. They have more average thrust to get this bird up to stable flight speed when it leaves the rod. In addition I can get a longer delay.

 

[heada]

I am definitely leaning towards just getting some E12’s. They have more average thrust to get this bird up to stable flight speed when it leaves the rod. In addition I can get a longer delay.

Look at the thrust curve. You want more thrust at ignition, not more average thrust. Only way to know that is to compare the curves.

Go to thrustcurve.org and look at the D12, the E9 and the E12. Then compare to something like Quest D22 or E26.

 

[brockrwood]

Look at the thrust curve. You want more thrust at ignition, not more average thrust. Only way to know that is to compare the curves.

Go to thrustcurve.org and look at the D12, the E9 and the E12. Then compare to something like Quest D22 or E26.

Good point.

 

[Back_at_it]

I found a 1990's era Estes "Maniac" rocket kit in my collection and I decided to build it. It is rocket kit 2091. Even the instructions are yellowed! It's vintage!

View attachment 485107

View attachment 485108

View attachment 485110

Anyway, the instructions say to fly the model on a D12-5, D12-7, E15-6, or E15-8.

I want to fly it on "E" engines. The problem: The only "E" engines I have are "E9-4" engines. These are vintage, too!

See pic.



I downloaded the Rocksim file for this rocket and simulated it flying on an E9-4 in OpenRocket. (Rocksim file from rocketreviews.com.)

The sim says that the velocity off the rod is 41.5 feet per second and the apogee altitude is 1,182 feet. The "optimum" ejection delay is 6.67 seconds (so the 4 second delay is a little soon for the ejection). The velocity at deployment is 89.4 feet per second!

So, what do you wise rocketeers think? Can I safely fly the Maniac on an E9-4? The speed off the rod is a bit low but I have a 4 feet long rod. The speed at deployment scares me.

I cannot find the Estes E15-6 and E15-8 engines on Estes' website. Are they not made anymore?

Should I just fly it on D12-5's and D12-7's? Bummer! I wanted to try my first "E" powered rocket. It would make me an official "mid-power" rocketeer!

The altitude of 1,182 feet seems really high. I can't imagine it will really get to that altitude. Will it?

(Oh, does anyone want a PDF or JPG of the instructions, card, or decals?)

Any advice?

Depending on how heavy you build it you could fly it on a C11-3 for really low small field flights. Mine is right at 6oz without motor so it makes a perfect small park flier on the C11-3 at around 250ish ft. It will be a relatively slow flight as well.

The D12-5 works great as well and it's the motor I fly mine on most of the time. Expect somewhere around 650ft. I also swapped mine to a 15in chute as I'm not concerned with breaking a fin on landing so it comes down pretty quickly. The new E12-8 motors will work just fine as well. Just make sure you have the room to recover as you're looking at 1200ft or more.

Keep in mind that there are a ton of great motors outside of Estes that work great if you want altitude. The At E20-7 is one of my favorites but you're knocking on the door of 1700ft.

 

[Back_at_it]

I also have a ‘yet to be built’ Maniac and some E9 motors. I’m wondering what the failure rate is of the Estes E9’s? Is it 1% , 10%, 50%? Or?

If it’s closer to 1%, I think I’ll risk it .

-Dave

Dave,, I've heard the reports of E9 failure vary. Some say they have never had an issue while others say they explode every other flight. I personally have flown a ton of them over the years and I've never had one fail. From what I understand, it comes down to how they have been stored and handled.

 

[neil_w]

A Q-jet D22 would work nicely I would think, or an E26 if you want to clear 1000'.

 

[jbr]

I flew a manic on a G40 to way up there, it simmed to over 5K
landed 3/4 mile away and recovered

 

[n3tjm]

I think it will fly fine with an E9. As others mentioned, the Estes E15 were shorter than the current E9/E12's. I really liked that rocket, I owned a couple of them. Unfortunately they were made during the time when Estes was using sub-par quality tubing.

 

[brockrwood]

Depending on how heavy you build it you could fly it on a C11-3 for really low small field flights. Mine is right at 6oz without motor so it makes a perfect small park flier on the C11-3 at around 250is ft. It will be a relatively slow flight as well.

The D12-5 works great as well and it the motor I fly mine on most of the time. Expect somewhere around 650ft. I also swapped mine to a 15in chute as I'm not concerned with breaking a fin on landing so it comes down pretty quickly. The new E12-8 motors will work just fine as well. Just make sure you have the room to recover as you're looking at 1200ft or more.

Keep in mind that there are a ton of great motors outside of Estes that work great if you want altitude. The At E20-7 is one of my favorites but you're knocking on the door of 1700ft.

Thanks! My problem with super high flights is that those flights dramatically increase the chance that I don’t get the rocket back. Not getting it back makes me sad.