My Level 1 Build and question thread - Mega Der Red Max

Well, I finally decided to take the dive and attempt a level 1 build. I know a few people here have done their level 1 on the Estes PSII rockets, and I personally love the DRM, so I decided to make my L1 the Mega DRM.

So first things first, time to glue together the balsa for the fin lamination:



As for the other part of this thread, I am hoping to gather advice to help me on my way to level 1. To get this out of the way though as I have seen it in other threads about the PSII kits:

Yes, I know these kits/29MM motor mounts are not the best for L1. No, I don't really care as I know it can be done.

As far as questions, my first one involves the recovery harness. I am not totally comfortable with a full Kevlar or a full Tubular Nylon harness. I feel there needs to be SOME sort of spring to the shock cord, so I want to go with a combination of both (Kevlar near the motor mount, Nylon at some point away from the motor.) Anyone have any experience with this form of harness, specifically how does one mate the Kevlar with the nylon?

Two things I'd suggest... Don't glue in your aft centering ring until after you glue your fins in place (and then do internal fillets). I'd also recommend that you build it with launch buttons rather than launch lugs.

Already planning on doing both. (Did the former on multiple rockets at this point, and the latter seemed obvious.)

I'd recommend you contact Teddy at Onebadhawk and get a tubular nylon harness with a Kevlar sleeve already installed like this one: https://www.onebadhawk.com/916-tubular-nylon-w-kevlar-sleeve--2-loop.html

Onebadhawk (Teddy) is a member on the forum and a great guy. He'll help you get what you need.

The MDRM is a great flyer and will be a great rocket for your L1. I got my L1 with one, although mine was very heavily modified and much heavier than stock. The 29mm motor mount is fine and perfectly appropriate for this rocket. Also, if you haven't already invested in motor hardware and don't want to right away, you can always do your L1 with a single-use motor. I used an Aerotech H115DM Metalstorm --- a cool sparky motor on the conservative lower end of H motors. It worked great!

Hi Tanarin, congrats on starting your L1 build. I am currently building a MDRM for my L1 attempt in the spring, so your thread caught my interest.

In terms of shock cord, my plan is to use a short Kevlar leader tied around the MMT that runs up through the upper CR, then tie the Estes supplied elastic shock cord to that. I simply use a square knot to tie the kevlar to the elastic, then soak the knot in a bit of white glue as added insurance that it doesn't undo. You could certainly do the same with nylon to Kevlar if you are against using the Estes shock cord. I like to use the elastic to avoid the cost of 25-30' of Kevlar but also enjoy its heat-resistant benefits. I've flown a Leviathan on F and G motors with the 'tea bag' attachment method for the Estes elastic shock cord without incident. This will be structurally more robust than the tea bag method but also makes use of the components that came in the kit.

Good luck, looking forward to comparing notes.

The MDRM is an awesome rocket. My mostly stock build has flown on H54's twice now with no problems The only thing I would add is to get an eyebolt and quick-links for the recovery harness. This will let you swap shock cords and use be able to remove the shock cord and use it in other rockets later. I've flown mine with the stock elastic cord before but now I'm glad I can switch to a new shock cord as the elastic is getting worn out.

One other thing: keep the 30" chute for other rockets and try at least a 36" chute in this. It's not uncommon for fins to break off on landing.

Good luck on the build and cert! What motor are you planning?
Here's mine flying on an H54 CTI 3 grain moonburner. One of the great things about this rocket is it's really light (mine's 36 oz with everything except motor) so you can fly motors that burn for long times that can't lift other 4" rockets.

These are great L1 rockets, they're practically made for it (minus a couple Ns.) A successful L1 flight is by no means impossible built stock, but I personally would change the shock cord to 1/4 kevlar.

Kevlar is good at eating a zipper in cardboard..
Me, I would going with tubular nylon with cardboard rockets.
I save the Kevlar for fiberglass rockets.

And I would triple check your delay time..

You only need an elastic shock cord if your cord is too short. With plenty of length, the ejection charge doesn't blow the nose out far enough to stretch the cord. Plus, with elastic, you can get bounce back, where the nose hits the airframe and damages it, or knocks the rocket off course.

ThirstyBarbarian said:

I'd recommend you contact Teddy at Onebadhawk and get a tubular nylon harness with a Kevlar sleeve already installed like this one: https://www.onebadhawk.com/916-tubular-nylon-w-kevlar-sleeve--2-loop.html

Onebadhawk (Teddy) is a member on the forum and a great guy. He'll help you get what you need.

The MDRM is a great flyer and will be a great rocket for your L1. I got my L1 with one, although mine was very heavily modified and much heavier than stock. The 29mm motor mount is fine and perfectly appropriate for this rocket. Also, if you haven't already invested in motor hardware and don't want to right away, you can always do your L1 with a single-use motor. I used an Aerotech H115DM Metalstorm --- a cool sparky motor on the conservative lower end of H motors. It worked great!

Click to expand...

A bit late on that. I managed to nab 10 yards of 5/8th Mil Spec tubular nylon for $10.95 shipped. So I feel kinda committed to a hand made solution at this point. As far as motor choice, I'm thinking of a 3 grain CTI case.

Tanarin said:

A bit late on that. I managed to nab 10 yards of 5/8th Mil Spec tubular nylon for $10.95 shipped. So I feel kinda committed to a hand made solution at this point. As far as motor choice, I'm thinking of a 3 grain CTI case.

Click to expand...

Keep in mind that CTI gives you a free motor casing the same size as your cert motor for first cert attempt. So pick a motor, and they will hand you a free casing. You'll need to pay for the aft closure.

Tanarin said:

Yes, I know these kits/29MM motor mounts are not the best for L1. No, I don't really care as I know it can be done.

Click to expand...

Yes, it can be done easily. That's not the point of those of us that recommend against it.

Come back in a year or two when you've flown a few of H and especially I motors. I expect your ideas about this will change.

Many of us try to impart the "wisdom" of our experience, but that is usually an exercise in futility. Experience can't be passed along, it can only be gained by doing. Go forth, have fun, and gain your own experience. That's what makes the hobby fun for everyone.

Good Luck with the L1!

Handeman said:

Yes, it can be done easily. That's not the point of those of us that recommend against it.

Come back in a year or two when you've flown a few of H and especially I motors. I expect your ideas about this will change.

Click to expand...

I didn't take me a year… I do like 29mm full H's more than 38mm H's but for I's 38mm is really the only good option.

I did my L1 with an Estes PSII kit, the Leviathan, with a 29mm motor mount. Here are the modifications I made:
1) Flipped the fins so they were pointing forward (didn't want one to break on landing and ruin my cert flight, plus I liked the look). Of course, that would ruin the classic DRM look, and I'm not sure if it would even be possible with your kit.
2) Put the flipped fin design in Open Rocket to check new CP position and verify stability on a 3-grain CTI H motor
3) Added an eyebolt to the forward CR for recovery attachment
4) Used kevlar cord (not tubular or flat webbing) instead of the provided elastic
5) Upgraded to one size larger parachute from TFR

My test flight on a large G motor went fine, as did my L1 cert flight on a CTI H54. Here's what has happened since then:
1) Got a nice zipper from the kevlar cord
2) Trimmed down the body tube to eliminate the zipper
3) Added nose weight to re-establish stability with the now shorter airframe
4) Attached a foam practice golf ball to the kevlar cord where it hits the edge of the airframe to protect from zippering again

I have flown it successfully in it's new configuration 6 times (4 G's and 2 H motors). It is still a fun flyer for me. Knowing what I know now, there is one more modification I would have made... a zipperless coupler design. I built a Madcow 2.6" DX3 after this rocket and incorporated a zipperless design, and I love it. With motor ejection and paper/cardboard tubes, the extra weight of the zipperless coupler is worth the durability IMO, as long as you are not going for max performace.

I would not shy away from recommending the PSII kits for L1 attempts if that is what someone wants to do. Yes, like many people after their L1, I wanted to fly bigger H and I motors and beyond. However, as a BAR, I'm hooked and will continue to build more rockets. I built my DX3 to take a 6 grain 29mm CTI case, and my current Level 2 project has a 54mm motor mount long enough for a 6 grain case. Some people will stay flying in the G and lower H motor range for various reasons, including their budget. If it's not what you want to do, why build your next rocket now? Enjoy this one and all the ones to follow!

To prevent zippers with a Kevlar cord, a simple solution is a small plastic ball (or something similar) slid over the cord so it will be near the top of the AF when extended. On much larger stuff, I use a tennis ball!

I did my L1 with a MDRM. stockish build with rail buttons, 1/4" kevlar shock cord and epoxy fillets on the fins. flew great on a CTI H133. it weighs 32oz without motor and flew 1000ft on the H133. I used the stock chute with no problems

I did the same as RKeller but with the stock shock cord too - no problems on an H133.

I also used the MDRM as my Cert 1 rocket. It is documented in the Certify with Us thread. Only thing I changed out of the kit was the cord. If I had to do it again, I would use a small u-bolt on the upper ring and a quick link.

Tanarin said:

A bit late on that. I managed to nab 10 yards of 5/8th Mil Spec tubular nylon for $10.95 shipped. So I feel kinda committed to a hand made solution at this point. As far as motor choice, I'm thinking of a 3 grain CTI case.

Click to expand...

Sounds good. I think you can buy a nomex cord protector sleeve if you want to add one. I've never bought one, so I do not know how they are attached. Or you could make a kevlar leader and attach your nylon cord to that.

Personally, If I had scored 10 yards of nylon for 11 bucks, I would be inclined to not worry about protecting it. It's not going to just burn through and separate on your cert launch or even after a few launches. It's going to slowly be damaged by heat near the attachment point, which is close to the ejection charge and also where the motor will continue to send hot gas even after the ejection. And eventually you are going to want to remove the damaged part. I'd suggest you to take your 30 feet and cut off around 6 feet. Tie the short piece to the nose cone and tie a loop in the other end of it. Now you have a leader for the nose cone that's about 5 feet long after the knots. Take the long piece and tie a loop at both ends so you have a shock cord that is about 22 or 23 feet long --- more than enough. Get a couple of quick links. Use one to attach the long cord to an eyebolt in the forward centering ring. And use the other to attach the long cord to the short cord and also to the swivel for the parachute. That's your recovery setup.

After every flight, just reach your hand down into the airframe and unhook the quick link from the eyebolt and check the nylon for burns. This is why a 4" airframe is so awesome! If the end looks fried, cut off the burned part, and tie a new loop. You can afford to keep cutting off damaged cord until it's about 15 feet long I would think.

The other thing that is cool about this setup, with everything attached by quick links, is that you can remove and replace anything quickly, and you can swap parts between rockets. So you can use your stock 30" parachute in the MDRM, or you can pull it out and use it in another rocket and swap in a 36" of 40" chute in the MDRM depending on conditions. It's really versatile. This is the kind of setup I use.

If you don't want to tie your loops you can also sew them or get someone to do it, but I understand it needs to be done properly, and I don't know what that involves.

This should be an excellent L1 project. A number of people certify on them. A couple things.

I fly my MRDM on H's all the time. When it comes to fin lamination on this kit USE EPOXY. Don't use wood glue. The wood glue when compressed under weight takes forever to dry and it will warp the fins. Use a 30-minute epoxy which will not warp the fins and will set in about 3 hours.

If you can get some Rocketpoxy, do so and use it for your fillets. as mentioned before, fins breaking off are not good and the rocketpoxy makes very strong fillets.

As far as shock cords go, and many people will disagree with me, get an additional elastic cord the same size as what comes with the kit. Tie the two together and you will be fine. You will want to anchor it strongly to the CR, but you are far less likely to zipper, and you won't have the weight of the nylon, plus you are less likely to break parts with a cord that isn't elastic.

I use a 36" PML parachute for mine, which has a vent hole in the center. This minimizes the diameter of the spin as the rocket lands which reduces overall velocity. Less likely to break a fin that way.

Around the forward edge of the airframe, "paint" the inside with some thin CA to strengthen it.

Use a drop or two of dishwashing soap and a cap full of rubbing alcohol in the pint of water you will use for your decals. In addition to getting the decal wet, also moisten the area the decal is to stick to. This will allow you to better slide the decal into place. Especially for the wrap decal, this will save you from teaching your children new words.

Strongly consider this: Cut the closed end of the shoulder off about 1/2". Replace it with a coupler tube bulkhead, but drill a 38mm hole in it. Find an inexpensive altimeter and mount it into the hole. Make sure there are vent holes to it. (A 1/8" vent hole in the airframe about 4" aft of the forward edge is needed anyway to prevent nose cone separation.)
Set an electronic charge to deploy the main at apogee, and use the motor ejection charge as a back up. this way the nose deploys right at apogee when the rocket is horizontal, reducing the risk of the nose cone smashing into a fin if it deploys after apogee.

I love to fly my MDRM on a Cesaroni H123 Skidmark. Makes a lot of noise, has a great flight, is barely an H so it doesn't go to high, and if there are 2-3 other MDRMs at the launch, having them all on H123s makes a cool drag race.

Take all the advice you've received thus far and will receive afterward to heart, but build it and fly it the way you want to fly it.

MDRM on a small 29mm H should do well as a cert flight combination. I've helped the kids build two of these. Used U-bolts as shock cord anchors, swapped out for Kevlar, and added buttons rather than lugs. Pretty sure we used epoxy for the lamination and TWT for fillets.


Later!

--Coop

ThirstyBarbarian said:

Personally, If I had scored 10 yards of nylon for 11 bucks, I would be inclined to not worry about protecting it. It's not going to just burn through and separate on your cert launch or even after a few launches. It's going to slowly be damaged by heat near the attachment point, which is close to the ejection charge and also where the motor will continue to send hot gas even after the ejection. And eventually you are going to want to remove the damaged part. I'd suggest you to take your 30 feet and cut off around 6 feet. Tie the short piece to the nose cone and tie a loop in the other end of it. Now you have a leader for the nose cone that's about 5 feet long after the knots. Take the long piece and tie a loop at both ends so you have a shock cord that is about 22 or 23 feet long --- more than enough. Get a couple of quick links. Use one to attach the long cord to an eyebolt in the forward centering ring. And use the other to attach the long cord to the short cord and also to the swivel for the parachute. That's your recovery setup.

Click to expand...

See, I did not think about this. I knew Nylon was not as good with heat as Kevlar, but from what I was reading, I was assuming that it did just burn through.

@EeebeeE: I would love to fool around with electronics, but I am trying to follow KISS as much as possible here, plus ATM storing "loose" black powder for such a charge is not really an option (Heck, I have to buy HP motors on site as is as the city charges a fee for me to keep HP motors.) I guess there is the CO2 option of course, but again, KISS is in effect here. I never thought about the CA for the tube though, THAT I may consider doing.

Tanarin said:

See, I did not think about this. I knew Nylon was not as good with heat as Kevlar, but from what I was reading, I was assuming that it did just burn through.

@EeebeeE: I would love to fool around with electronics, but I am trying to follow KISS as much as possible here, plus ATM storing "loose" black powder for such a charge is not really an option (Heck, I have to buy HP motors on site as is as the city charges a fee for me to keep HP motors.) I guess there is the CO2 option of course, but again, KISS is in effect here. I never thought about the CA for the tube though, THAT I may consider doing.

Click to expand...

The tubular nylon is more resistant than the very thin nylon of a parachute. One ejection charge will completely destroy a chute, but not tubular nylon. I used an unprotected nylon shock cord for several flights in my MDRM before buying the one with the Kevlar sleeve. It was starting to get a little bit toasted on the surface, but not bad, and I still have it and am using in an different rocket now.

If you use an eyebolt in the centering ring as your anchor, it will be off to the side and not in the direct path of the ejection. I think that is probably better for an unprotected nylon cord than using a u-bolt that goes directly over the motor tube and is right in the path of the ejection.

You should still use some dog barf to absorb the worst of the ejection. And you should use a 12" nomex blanket to protect the chute. I put a couple of squares of wadding right over the forward opening of the motor tube. Then add a few handfuls of dog barf on top of that. Then the z-folded shock cord and the nomex burrito containg the chute --- I slide those in side by side. Then the leader to the nose cone on top of it all.

Make sure the nose cone fits into the tube nice and snug, not loose. Add a strip or ring of masking tape around the shoulder of NC if it feels loose. You want a pretty good seal, not so loose the NC can just fall out, but not so tight the NC is stuck! The ejection charge does not actually blow all of the recovery gear out of the tube like a cannon. Instead, it pressurizes the space, and the NC pops out like a cork from a champagne bottle. That's why you want a decent seal. The momentum of the NC yanks on the leader and pulls out the parachute burrito, followed by the shock cord. It's a thing of beauty!

ThirstyBarbarian said:

Make sure the nose cone fits into the tube nice and snug, not loose. Add a strip or ring of masking tape around the shoulder of NC if it feels loose. You want a pretty good seal, not so loose the NC can just fall out, but not so tight the NC is stuck! The ejection charge does not actually blow all of the recovery gear out of the tube like a cannon. Instead, it pressurizes the space, and the NC pops out like a cork from a champagne bottle. That's why you want a decent seal. The momentum of the NC yanks on the leader and pulls out the parachute burrito, followed by the shock cord. It's a thing of beauty!

Click to expand...

Indeed! Here's two photos of a deployment sequence on another 4" rocket:

Handeman said:

Yes, it can be done easily. That's not the point of those of us that recommend against it.

Come back in a year or two when you've flown a few of H and especially I motors. I expect your ideas about this will change.

Many of us try to impart the "wisdom" of our experience, but that is usually an exercise in futility. Experience can't be passed along, it can only be gained by doing. Go forth, have fun, and gain your own experience. That's what makes the hobby fun for everyone.

Good Luck with the L1!

Click to expand...

I agree completely that, if you are really into Level 1 you should build a fully level 1 rocket. However, if you already own a rocket that could be cool with a 29 mm H, why wait? You know how awesome a H250 is in a Leviathan .

RKeller says "it weighs 32oz without motor and flew 1000ft on the H133" ... sounds like to me if someone really wants to fully fly a MDRM, you can't do it without L1.... as limiting as that might be. You could go for a true HP rocket about that same size, but it would barely fly on MPR G motors.

I'm hoping to get my L1 next launch. There isn't any I motors in the plans, but definitely Skids :dark:.

bill_s said:

I agree completely that, if you are really into Level 1 you should build a fully level 1 rocket. However, if you already own a rocket that could be cool with a 29 mm H, why wait? You know how awesome a H250 is in a Leviathan .

RKeller says "it weighs 32oz without motor and flew 1000ft on the H133" ... sounds like to me if someone really wants to fully fly a MDRM, you can't do it without L1.... as limiting as that might be. You could go for a true HP rocket about that same size, but it would barely fly on MPR G motors.

I'm hoping to get my L1 next launch. There isn't any I motors in the plans, but definitely Skids :dark:.

Click to expand...

I totally agree. The MDRM (and other pro series) does fly great on H's. I do sometimes wish it was 38mm though, just to have to option to fly larger motors. If "fully fly" means to clear 1000 feet you definitely need L1 motors for the MDRM, and it could probably even fly a 29mm I motor.

SCrocketfan said:

I totally agree. The MDRM (and other pro series) does fly great on H's. I do sometimes wish it was 38mm though, just to have to option to fly larger motors. If "fully fly" means to clear 1000 feet you definitely need L1 motors for the MDRM, and it could probably even fly a 29mm I motor.

Click to expand...

I made daughters Mega Der Purple Max a 38mm - it has already flown on a H400.

Next up is a H550ST and hopefully some electronics to see how high and fast it goes.

It started off as a stock tube and nosecone, but tube got wrapped and fins got a layer of fg also.

Kenny

SCrocketfan said:

I totally agree. The MDRM (and other pro series) does fly great on H's. I do sometimes wish it was 38mm though, just to have to option to fly larger motors. If "fully fly" means to clear 1000 feet you definitely need L1 motors for the MDRM, and it could probably even fly a 29mm I motor.

Click to expand...

I've flown mine on an I200, built stock except shock cord & attachment. My favorites, though, are the H182 DMS & H210 RMS redlines.

Yeah, I am still on the fence as to what I want to cert on. Either way I would need new hardware, but I am also on the fence about just certing with a DMS to start. Big problem I have with DMS though is the fact that it seems like the drill tool can only be used on DMS motors (and costs an extra 10 bucks for what would be likely one or two uses max.)

CTI reloads on the other hand I have no experience at all with, but I like what seems to be a higher array of choices. Also nice that there is a starter kit for CTI that

AT also looks nice, but I am confused on a few things. I am assuming that I could not use hobbyline reloads (With appropriate spacers obviously.) in a HP case or even vice versa with the 60/100/120 HP reloads in the Hobbyline case (With appropriate spacers obviously.) Other main problem is the fact that there seems to not be any starter set for AT.

Edit: I think I just found a deal on both a case and Spacer system for Aerotech loads, but the case is Rousetech, will that be an issue (Assuming not, but figured I ask)

Rousetech cases are the same as Aerotech only made by a different manufacturer. The CTI loads are great, the 3G small H's provide plenty of options for a cert and you can get the starter set or get the case free as a certification special.