Estes Ventris Build - First Mid Power Rocket

[Fred Garvin]

I've always only built and flown smaller rockets, up to D & E power.....mainly B & C motors....with 1 out of 10 flights being on a D or E motor. I've never flown F & G motors or built a rocket capable of them. I had some unexpected cash drop in my lap last week so ordered an Aerotech Initiator Kit from Wildman....and while waiting on it, found a Hobby Lobby 40% coupon and bought a Ventris for $35. This will be my first foray into Mid Power and first step beyond LPR.



This is a big kit. (For me) Everything in it is bigger, stronger.....it's the same concept as the LPR's, but just scaled up with stronger materials. I'm impressed with the upgrades in fin stock, centering rings, motor retainer, really nice chute, heavy duty shock cord....this is cool! (and big)



First part of the process is the motor assembly. Easy to assemble, just be careful lining up the rings to where they're supposed to be. There's no measurements in the instructions, just telling you where to put them, using a green collar to line them up in the proper position, and the fins to get the correct spacing at the aft end.



Looking ahead in the instructions, the motor block ring is optional, and there's no instructions on exactly where to install it. I would guess, use a motor like a G80-7 inserted into the assembly, and position the ring just forward of it? Or, not use it at all? What have other Ventris builders done?

I'm not going to use the tri-fold paper glued attachment method for the shock cord. I'm going to get a Kevlar leader mounted to the centering ring on the motor assembly, attaching the shock cord to that instead. Otherwise I do plan to follow the instructions and build as designed....unless there are some "gotcha's" others have solved before me.

 

[mcderek]

Leave the thrust ring out then you can fly longer motors. CTI 3 grains are sweet in the Ventris.

 

[samb]

Yes, internal thrust rings are optional because the motors have an aft thrust ring that serves to keep the motor from moving forward in the motor mount tube.

single use has a molded ring:



the aft enclosure of a reload case performs the same function:

 

[Fred Garvin]

Brilliant...thanks guys....love this place!!

 

[samb]

Many kits with through the wall fins have you position the center and aft centering rings on the motor mount tube so that they butt up against the fin tabs. This additional gluing surface keeps the fins locked in. A lot of build threads show the technique for doing internal fillets where the aft centering ring is not glued on right away.

This post and the replies have some good diagrams and links:

https://www.rocketryforum.com/showt...-Mount-Fin-Fillets&highlight=internal+fillets

 

[samb]

...
Anyway, it's funny to see everyone who's building one of these post their question about the thrust ring. I posted the same question as have many others! Never having used anything other than BP motors I didn't know about the rear ring!

Sorry I missed your earlier question pick1e. Who's in charge around here anyway ?!? :duck:

ATTENTION ALL CURRENT AND FUTURE TRF'ERS WHO MAY NOT KNOW: internal thrust rings are OPTIONAL. If the motor you're using doesn't have an aft thrust ring you can make your own with tape. About a gazillion examples here and other places like the Apogee site. :grin:

 

[Fred Garvin]

.... everyone who's building one of these post their question about the thrust ring. .....

When I created this build thread I thought "man, another Ventris thread?"......but it is my first MPR and post in the MPR forum and I knew I'd have some questions.....it also makes me feel a bit more comfortable knowing more experienced rocketeers are keeping an eye on me as I go......

 

[cerving]

No worries, the fact that the same questions keep getting asked means that there are more people coming into the hobby, this is a good thing.

When you get ready for your L1 cert (and you CAN do it with your Ventris if you build it carefully), there will be plenty of people here to help you with that as well.

When I created this build thread I thought "man, another Ventris thread?"......but it is my first MPR and post in the MPR forum and I knew I'd have some questions.....it also makes me feel a bit more comfortable knowing more experienced rocketeers are keeping an eye on me as I go......

 

[dgreger]

And remember, there's no such thing as a stupid question, everyone here is always eager and willing to help out a fellow rocketeer!

 

[samb]

Well, I did go back to pick1e's 2012 Ventris thread to make sure I gave you the same answer about the thrust ring . No worries, no demerits for asking the same question ! I know it was a "D'oh!" moment for me when I first learned about aft thrust rings.

 

[JumpJet]

internal thrust rings are OPTIONAL.

This ring was included in the kits because I knew Estes was coming out with 29mm Black Powder motors that could be used to flies these models with. If you wrap tape around the end of the black powder motors you wont need a thrust ring. If like me you know the largest motor you will be flying this model on is say an Aerotech G80 motor, I would install the thrust ring to accept the G80 motor and make a 29mm composite to 29mm Black Powder Motor spacer which are a .5" difference in length. Then it's a simple matter to switch between composite and Black Powder motors.

John Boren

 

[samb]

This ring was included in the kits because I knew Estes was coming out with 29mm Black Powder motors that could be used to flies these models with. If you wrap tape around the end of the black powder motors you wont need a thrust ring. If like me you know the largest motor you will be flying this model on is say an Aerotech G80 motor, I would install the thrust ring to accept the G80 motor and make a 29mm composite to 29mm Black Powder Motor spacer which are a .5" difference in length. Then it's a simple matter to switch between composite and Black Powder motors.

John Boren

Tips from the designer are always appreciated. Thank you.

 

[Fred Garvin]

Tips from the designer are always appreciated. Thank you.

And in my first ever MPR build thread....wow.... :grin:

 

[Initiator001]

And in my first ever MPR build thread....wow.... :grin:

If you had received your AeroTech Initiator sooner I could have chimed in. :wink:

 

[Fred Garvin]

If you had received your AeroTech Initiator sooner I could have chimed in. :wink:

I'll be starting one for it....still waiting on WM to ship it....but I'm really looking forward to building and flying it.....I'm sure I'll be building an Aerotech Fleet.

I hope nobody though I was poking fun at you, I was just poking fun at the fact that they include that ring and everyone is like :confused2: It's just humorous that we all cross the same bridge!

Carry on!

Nah, don't think so....it is nice that we're all on the same wavelength though....

 

[Rex R]

here is a tip for those unaccustomed to working with slotted body tubes and through the wall fins; resist the temptation to make the slots wider until you have finished your preliminary fin sanding, if you widen the slots early the fins will tend to wobble, you'll find it easier to get the fins glued if the slots are a smidge tight(but not so tight that the tube deforms).
rex

 

[Fred Garvin]

Nice tip, thanks....

Got a chance to do more work in the shop tonight:



Started assembly of the upper portion of the rocket....nose first....



Then installed the motor assembly into the lower slotted body tube....



Then the transition coupler, body tube coupler, and launch lugs....



I'll let everything setup well overnight so I can start working on the fins tomorrow......have to sand and shape them before installation....and I'm gonna take my time with each fin to make sure it's exactly properly aligned and set before moving to the next one.

 

[Rex R]

I sort of got the impression that Estes figured that most beginners would wait and sand the flats of the fins after they were installed, since the slots on my ventris did not need widening(little loose after I filled and sanded my fins)...which is why I mentioned it. if you're like the rest of us, you'll probably dry fit the fins just see how the bird looks . have fun,
rex

 

[Fred Garvin]

I sort of got the impression that Estes figured that most beginners would wait and sand the flats of the fins after they were installed, since the slots on my ventris did not need widening(little loose after I filled and sanded my fins)...which is why I mentioned it. if you're like the rest of us, you'll probably dry fit the fins just see how the bird looks . have fun,
rex

I sand and shape my fins before I install them....test fitting beforehand as well. They're much easier to work with before they're glued up. Depending on the model, I'll use sanding sealer....I use Aero Gloss....

 

[Fred Garvin]

Personally, I glue and fillet my fins before sealing and filling them. I wouldn't be able to sleep at night knowing the glue was holding on to filler instead of the wood grain. But doing it the other way would definitely make life simpler. Same with filling spirals- I do it last, some do it first when it's 10x easier

I glue them up after sanding and shaping so the glue adheres to clean raw wood.....once installed and filleted....THEN I use sanding sealer......

 

[Fred Garvin]

Started working on the fins today. They're pretty rough out of the box, but at least they're cut out and shaped.....



On the left the fins are sanded and leading edges rounded.....on the right in raw state out of the bag. These aren't like easy balsa in LPR kits, they're a plywood, 3 layers. Given a good sanding with 220, a bit of rest for the wood to calm down and the grain to raise, then a follow up with 400, they come out silky smooth and clean. Once I get them glued and filleted to the lower slotted body tube/motor assembly...I think they'll take the Aero Gloss very well and produce a strong, smooth fin.

 

[ereinert]

Hey Fred, Thanks for pointing me to this thread. Very similar to my current build. Following your build has answered a lot of my questions. I'm surprised at how much different a MPR build is to a LPR. I'm loving the challenge! Good job my friend on your Ventris! I know my biggest learning curve is coming with choosing my first motor and putting it together but I will deal with that when that time comes.

 

[Fred Garvin]

Got a fair amount done today. Mounted up the fins:



Mounted up the first as a reference, then using my jig and a level got the other 3 installed...it took several hours because I let each one setup well before moving on to the next. Also, attached the upper body tube.



The extra effort was worth it as I got them as close to perfect as I've ever done any rocket.



Hard to get a picture of them as any bit off in the camera angle and it translates to the fins...anyway, last tasks for the evening are launch lugs, fillets, and epoxey'd the motor retainer in place.

 

[Fred Garvin]

Hey Fred, Thanks for pointing me to this thread. Very similar to my current build. Following your build has answered a lot of my questions. I'm surprised at how much different a MPR build is to a LPR. I'm loving the challenge! Good job my friend on your Ventris! I know my biggest learning curve is coming with choosing my first motor and putting it together but I will deal with that when that time comes.

Thanks.....I'm following your build thread 'cause we're in the same boat...so to speak....

I've got Rocksim....and all my fleet's .rkt files.....I can run a variety of motors for a given day's conditions (and limitations) and choose a motor....

 

[Fred Garvin]

Nice 4 day weekend....a hot, humid Texas summer afternoon....nothing I'd rather do than spend time inside working in the Rocket Shop.

Spending time sanding and applying sanding sealer to the fins:



Working on the nose section while the Aero Gloss dries between coats:



Sanded....primer'd....will be ready for color coats in an hour or so.....

 

[Fred Garvin]

Finished up the nose section. Went with Cherry Red and several coats of clear....smooth and slick.



The main sustainer is finished and primer'd....a light sanding and the color coats will start later today.

 

[scsager]

Looking Good !! need sunglasses for that hi-gloss finish!

 

[ereinert]

Look'n good Fred! Can't wait to see the final product! Very nice..

 

[Fred Garvin]

Thanks! Got the color coat on the main body. Once it cures properly, I can mask off and shoot the fins. They're going to be Cherry Red like the nose.



Almost done....hopefully I'll get to fly it at the next range day on the 20th!

 

[samb]

Looking very sharp FG. I appreciate the relative increase in clutter on your workbench, but the cutting mat looks like you could eat off it ! Ugh! Another craftsman on TRF. :cry: :clap: