# Estes V-2 Mods for use with F engines

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#### RocketSmokEater

##### Well-Known Member
I'm new to the forum, although I've done a lot of reading on various threads/posts. I'm getting back into rocketry from my Estes low-power days 10 years ago or so, so i thought to try mid-power but also keep the "bigger" Estes kits around as well.
I apologize for the length of this IN ADVANCE!! ;-)

I know there's been lots of posts on various V-2 mods - all of which i've read - but wanted to get some more specific feedback since i'm new to mods and such. I'm looking to fortify an Estes 4"
V-2 kit i bought recently to fly on Aerotech F engines. From a lot of folks I've heard the F-21 Econojets (or even the E15s and E30s from what i hear) are great engines for this kit, and i believe this is the engine i'd like to mostly fly the V-2 on given it's impulse, apogee ratings, and safety from lots of reports of crashing like the E-9. Anyway I'm curious as to what I need to do to strengthen all the necessary parts that need to be strengthened for longevity and nice upward flights. People have told me different things, as opinions vary completely of course, and I'm thinking light and strong. So, here is a list of parts, including construction materials and techniques i'm thinking to implement, glues and such that i want to inquire about etc. If you notice i missed an important part, by all means please mention it:

- 4" BT upper interior CyAing and upper interior MMT (thin runny & odorless brand), after assembly of MMT of course, which strengthens BT and protects from repeated ejection gases, and then followed by some nice smooth sanding

- replacement of stock cardboard rings with basswood or simliar material, or even doubling up the cardboard ones by making a new set of my own and gluing together, including the smaller, tail end ring? use of epoxy on this assembly?

- constructing and mounting the engine assembly as intended for the E, but with dual E engine clips for retaining an F which i believe is same dimensions as the E - 24mm x 3.75" - and keeping the same engine block and all?

- fins fins fins. lots said on these. thinking it's better to just build them stock though strong. plastic model cement sandwhiched together or CA or any other type of glue? definitely some nice light, though strong layers of 15-min epoxy filletted smoothly to the BT...?

- and i'm thinking about a nice 30-36"? nylon parachute/chute protector/kevlar system from Top Flight or Giant Leap. kevlar mounted to either eye bolt on upper ring or slitted through it and epoxied directly to MMT?

- i'll worry about painting schemes later! ;-)

The idea is not to go crazy with mods that aren't necessary, though enough strengthening with materials and the right glues that will keep it light, strong and to last. Of course, anything can happen in the air regardless how much work i put into it! ;-)

Thanks everyone!

#### cls

##### Well-Known Member
I'm sure you will get at least $2 worth of replies, here's my$0.02:

V2 is designed to 1) carry a warhead 2) fit on a railroad. 2) doesn't leave much room for large, effective fins; most people don't put 1) in their model rockets. so that's 2 strikes on the V2 design before you've even started building it.

I think your construction plan is a good one. but beware, all those things add weight, and the weight is in back where you don't need it and the fins can't fight it.

so when you are done building, load it up as it would be ready to fly, and check the CG. be prepared to put some weight in the nose. BBs or little fishing leads work great. measure first then mix with epoxy and just pour them in to the nose cone.

#### rbeckey

##### Well-Known Member
I used epoxy to fill those fin base areas also. I mixed Sig microballoons in a 50/50 ratio with the epoxy and it worked quite well. I would guess that it is 40% or a little more lighter than epoxy alone.
Consider filling the fins with something. There had been much said about it, as you saw.
As an aside, a have heard of the fabled F21 Econojet, but I have never actually seen one offered for sale. Rumors abound, but I am beginning to doubt their veracity.

#### LaneKG

##### Well-Known Member
I finished my 4in Estes V2 with the following mods:

Used loc 29mm motor tube with loc centering rings

Put a loc 3in centering ring inside tailcone at the bottom

Put T nuts in the 3in centering ring for retention clips

Put sytrene sheet between fin halves (Sandman tip)

Used Apogee Fixit epoxy clay for fillets on fins

Put an eyebolt on upper centering ring

Used Pratt chute protector cloth

Used a 36in Spherachute

Lots of weight in the Nosecone

The result was a 1.9 lbs rocket. I flew it on a G80-7 and it was a great flight. Now I think I will try it on a H motor.

Thanks,

Greg

#### Ryan S.

##### Well-Known Member
I didn't do one thing to my V2 and have flown in multiple times on F21s. The fins cracked a few times but I just took a little cement and stuck them back together. put some expanding foam in there and that could help. with that problem.

Like others have said the weight could pose a problem. so I wouldnt add too much to the back of the rocket because then you will need to add weight to the front which will bring up the weight of the whole rocket

#### LaneKG

##### Well-Known Member
Detail on Greg's V2 mods

#### LaneKG

##### Well-Known Member
Another detail on Greg's V2 mods showing epoxy clay fillets.

#### Stones

##### Well-Known Member
Originally posted by RocketSmokEater
- 4" BT upper interior CyAing and upper interior MMT (thin runny & odorless brand), after assembly of MMT of course, which strengthens BT and protects from repeated ejection gases, and then followed by some nice smooth sanding
Good idea. I made a thin epoxy coating for inside the BT.

- replacement of stock cardboard rings with basswood or simliar material, or even doubling up the cardboard ones by making a new set of my own and gluing together, including the smaller, tail end ring? use of epoxy on this assembly?
I used the stock rings (cut to fit the 29mm MMT), except for the smaller ring on the boattail, I replace with 3/32 basswood.

- constructing and mounting the engine assembly as intended for the E, but with dual E engine clips for retaining an F which i believe is same dimensions as the E - 24mm x 3.75" - and keeping the same engine block and all?
Scratch built a 29mm MMT and coated the inside with heat resistant paint. I did use an engine block cut from a used 29mm motor. Also a scratch built Aerotech type motor hook. I used a tiewrap around the motor and hook for extra security.

- fins fins fins. lots said on these. thinking it's better to just build them stock though strong. plastic model cement sandwhiched together or CA or any other type of glue? definitely some nice light, though strong layers of 15-min epoxy filletted smoothly to the BT...?
Sandwiched 1/16 basswood in the fins. Leave some extra material around the fins when you trim them from the sheet. It'll be alot easier to glue them this way. Then sand the edges to the desired finish. Epoxy fillets.

- and i'm thinking about a nice 30-36"? nylon parachute/chute protector/kevlar system from Top Flight or Giant Leap. kevlar mounted to either eye bolt on upper ring or slitted through it and epoxied directly to MMT?
I used a scratchbuilt 40" ripstop, along with a 12"x12" nomex blanket. I like my birds to come down nice and easy.
Weight is 22.6 oz. w/o motor. 3.5 oz. of that is noseweight. She flew like a champ on an F20-4.
Here's the flight. V2 on an F20

#### Ryan S.

##### Well-Known Member
Nice mods dude, I wish I had done that to mine. I would love a V2 that would take Hs and some Gs. My 5.5" needs a minumum of an I because it is so heavy, so I need a V2 for Hs.

Man I love that rocket

#### RocketSmokEater

##### Well-Known Member
for those of you who responded specifically to the questions i had thanks.

CLS: yes i'm trying to keep the weight down with materials and such, without piling on epoxy and such. could you tell me a little about how the weighting/testing of the CG is done after assembly, of couse with the motor mount, wadding, and parachute assembly prepped? in other words, when it's ready to fly, what would be a pretty accurate way to swing test it or what not in order to add some epoxy clay inside the nose cone? i don't even know where the CG technically is supposed be...?

STONES: thanks for all your detailed responses, though i'm sticking to the 24MMT for the F-21s, incase you missed that! ;-) still curious about some things though....
1) how do you suggest pouring in the thin (and hopefully odorless Cya i might find at Home Depot?) inside the BT? i know it has a great water consistency but might dry quick, leading to lots of drops and unsmooth coating? should i just do 2-3 coats and sand heavily?
2) interesting you kept the stock board rings - honestly, they're pretty durable and have that nice seemingly glassine finish...? i was thinking about doubling up on them by maybe calling Estes to have them send me a whole new set (2 large ones and 1 for the boat tail) to make it extra durable, but don't think i may need to? why did you replace just the boat tail/smaller ring with basswood - lots of forces there that could use strength? is it really necessary?
3) for the fins on 24mm F power, better the 1/16th basswood or that green styrene people have talked about? any difference? i'd think the styrene is lighter. either way, do i just cut the material to fit EXACTLY inside the fin die cuts or what? and after cutting out the fins do i just glue one side to the basswood/styrene with Cya, light epoxy, or plastic cement? how is that done?
4) would Apogee's epoxy clay suffice for fillets?

LANEKG: the colors on that camo paint scheme look beautiful! really rugged. i enjoy the light lime and olive green tones and the light brownish grey ones as well. could you somehow get me the paint #s on that?! i'd love to buy a nice airbrush kit and use the exact colors for mine!

thanks guys and hope to hear back!!

#### Stymye

##### Well-Known Member
you might try the epoxy with a lightweight filler on the fillets to help keep it light enough.. and mabey save the epoxy clay for noseweight

annother idea is internal balsa ribs running lengthwise to help strengthen the thin bt 101 without adding alot of weight
thin cya is a great idea also. a single application should work
it soaks in fast..beyond that you are merely building up the cya layer...ventilation is important ,don't look down the tube as your applying it ,,trust me on that.ouch!

I also used the stock rings on my first V-2,coated with glue
no probs so far

I have filled the fins with expanding foam ,lots of options

make sure to take some pics!

#### LaneKG

##### Well-Known Member
Originally posted by RocketSmokEater

LANEKG: the colors on that camo paint scheme look beautiful! really rugged. i enjoy the light lime and olive green tones and the light brownish grey ones as well. could you somehow get me the paint #s on that?! i'd love to buy a nice airbrush kit and use the exact colors for mine!

thanks guys and hope to hear back!!
I used the Krylon Camouflage System woodlands scheme

Khaki 8141
Olive 8143
Brown 8182
Black 8140

You have a good set of eyes, I don't pick up colors that well. This was a minimum effort approach for painting the V2 in camo. The paint was availble at Walmart.

Greg

#### OccamMD

##### Well-Known Member
Greg,

I just used the same paint and scheme from Walmart, How did you get the soft edges? I ended up with a build up by the time I got to black and obvisouly put too much on. I just made masking tape decals layer by layer, but I need to work on my technique a lot!

Thanks,
Ray

#### LaneKG

##### Well-Known Member
Ray,

I just covered the V2 with the Khaki and then eyeballed blotches of the other three colors. I did not mask anything.

Greg

#### cls

##### Well-Known Member
if the rocket were a windvane, then the CG would be the hinge, and the CP would be in back of that, towards the vane. if the CP is in front of the hinge, towards the arrow, then the rocket will be unstable.

finding CG:

it's just the "balance point", where the fully loaded ready to fly rocket balances. smaller rockets you can just put them on the edge of a ruler.

finding CP:

if you haven't found EMRR then you must check it out: http://www.rocketreviews.com/

a quick search there shows a wealth of information about the Estes E V2 kit. a couple CPs are offered: 18" and 23". (by convention CP is measured from the nose cone.) hmmm! when the numbers are that far apart it makes me wonder, what is the CP really?

another way is to use Rocksim or another simulation program to figure out the "lateral area" of the rocket nose cone, airframe, and fins - and use the calculated CP. EMRR has rocksim files for many many rockets.

yet another way is to cut out a cardboard silhouette of the rocket, find the balance point of that, and that's the CP!

the CG needs to be at least 1 body tube size ("caliber") in front of the CP.

what I remember for the V2 is the CP is about an inch in front of the top of the fins. somebody correct me if that's wrong! the V2 is 4" diameter. 4"+1"=5"; +1" for extra = 6"

bottom line: add weight in the nose cone until your V2 balances 5 or 6 inches in front of the fins.

you can try the swing test too: tie a string on at the CG and spin it around. it ought to fly "forward". if not add more weight and do it again.

hope that helps!

#### OccamMD

##### Well-Known Member
Greg,

How far back where you from the rocket when you sprayed it?

BTW, I love that Krylon, I had never seen it. I spent \$8 on olive drab for my honest john at the hobby store, never again!

I want to make an inititaor next with the Snow camo scheme.

#### RocketSmokEater

##### Well-Known Member
has anyone ever used or heard of the following brands of glues?
i just picked some up after researching and talking with the owner of my hobby shop and he claimed this is good stuff for my purposes:

1) "Flexible Thin", 2-5 sec. CyA Glue, just like water viscosity that i can pour (for inside protection & rigidity of upper BT and MMT/stuffer tube). it's the "flexible thin" that concerns me - will it suffice and last? the 2-5 seconds is pretty typical for fast drying. being that it's water consistency should coat most of the side evenly, then some sanding.

2) no microballoons can be found in my area. heard baking soda is excellent substitute - interesting to say the least! anyone ever try this mixture to use for centering ring/MMT assembly and fin/BT mounting fillets? if so, how much baking soda per part epoxy?

3) for the V-2 plastic fins: this space age "super fast-drying formula" was recommended to me as a "space age plastic welder" that basically fuses the two plastic fin halves together. it's "excellent for plastic sheets". it's called "TENAX - 7R" in small clear bottle, yellow label and black cap - 1 fl. oz. supposedly you can just cut out the fins exactly the right size, tape them together to sand them flush all around (leave tape on temporarily), and then slowly brush some on directly to the outside edges (and inside the seams too if desired) and it will mold/fuse together SOLID. no melting or anything, just fusing....? does this seem ok? definitely better than the weak plastic cement that i've heard melts and/or comes apart.

4) i can't find that PML 2-part foam that everyone seems to suggest. looked at 2 hobby shops and Home Depot - nothing. thinking that plastic welder i bought may suffice without filling...?

LaneKG/Greg: thanks for the color numbers of that krylon paint - and for the compliment on good eyes - an artist/designer must know his tones! ;-) i'll see if i can find that Krylon at Walmart (or Target i'd assume is possible) - it really looked excellent given the MANY other camo schemes i've seen. this is exactly what i'd like to try. i'll let you know how i do and possibly post some pics. also, as OccamMD asked, i too am curious as to how far you were from the rocket for each color spray since you didn't mask anything...? those soft egdes really are great, and ideal! how did you deal with itty bitty annoying overspray with all the colors? and after sanding the entire rocket (plastic nose and tail and fins) did you prime it, or considered the khaki color the primer? how many coats of everything? i'm not at the painting stage yet, but this thread is up for reference when i need it!

CLS: thanks for the detailed process of finding CG and CP points. i'm still a bit fuzzy as to how to do that exactly after light mods, but i'll hit you back when i'm at that point. for now, the mods experience is to be gathered!

thanks everyone!
ps - sorry for the long posts (although i've seen worse).
currently in process of learning what's best and getting everything together! ;-)

#### LaneKG

##### Well-Known Member
OK folks,

On the V2 paint I just put a dowel in the motor mount, held the dowel in the left hand and sprayed the paint from the usual 10 inches. This was suggest by someone on RTF. I was really taking a short cut to get it done in lieu of masking. I can't remember if I used one of those spray can handles, but I bet I did. I think I did two coats of the khaki, but you only get one chance on the remaining colors.

You might want to try this scheme on a spare tube to see what you think. It actually could have used some wet sanding but I did not do that either. I did put some dullcoate clear on it.

Greg

#### astronboy

##### Well-Known Member
Hey Guys: Good news on the Aerotech F21s!! Joe Burger has just posted that they will be shipping in two weeks!!

Here is the thread of the latest AT shipments:

As for the many suggested mods, all are excellent, as long as you keep in mind what the ultimate purpose of the rocket will be: If you are going for 29mm, I say OK to the epoxy coatings, and the wooden fin inserts (orexpandable foam). I think that they are needed for this sized motor.

If you are sticking with 24mm, these mods may require too much nose weight to make them worthwhile. I have not filled my fins, or epoxied anything but the engine block. I did soak the inside of the BT with thin CA for some strength. The only other mods are a 36" nylon chute, double engine hooks, and plenty of shock chord. With these mods, no nose weight is required, and the rocket is stable.

I fly my original ESTES Maxi Brute V2 using the F21-6W and am very pleased. here is a liftoff pic from last summer:

#### RocketSmokEater

##### Well-Known Member
can anyone say whether or not an eyebolt with washer/nut combo will suffice to screw in and epoxy on upper 1/8" thick cardstock CR of my V-2, and the forces won't rip it off, shred it or do any damage flying on an F-21? what i did was double up on the Estes's V-2 1/16" cardboard/paper rings by cutting out another set from thick cardstock photo matte backing. i plan on sandwhiching them together flush with some wood glue spread evenly between each set of rings.
the recovery system i'm thinking is going to be short tubular kevlar anchored to upper CR via the eybolt mentioned above, followed by kevlar chute protector, the 36" rip-stop nylon panel chute, and about 12' of tubular nylon via quick-link/eye bolt on NC - all by Giant Leap rocketry. maybe the eye bolt, even with epoxy and nut will be bad idea? slit through upper CR and epoxy to MMT a better idea?

by the way, this V-2 is the 4" version

thanks!

#### Zippy

##### Well-Known Member
If I were going the I-bolt route I'd want to back it up with some scrap wood to spread the forces out more on the centering ring. It wouldn't be a problem if your ring was wood but I'd be worried about it pulling through paper. Notching and epoxying the cord to the MMT is how I've done it on all my mid/high power rockets so far with no problems. Of course it makes it difficult to replace the cord should it ever be necessary.

#### astronboy

##### Well-Known Member
I agree. The bolt will focus all of the energy of the shok ricght around the nut/washer area. If I were using an eyebolt, I would have a 1/8" lite ply ring custom burned by BMS for a few bucks:

http://www.balsamachining.com/

Bill at BMS makes custom sings for me all the time. They are cheap, and easy to order: just fill out the spreadsheet and email it to him!!
F

#### RocketSmokEater

##### Well-Known Member
thanks for your responses astronboy and zippy. the cardstock i was referring to is definitely extra strong, at least much better than what i've seen before, and coupled with the stock ones. is 1/8" lite-ply generally heavier than both balsa and basswood?

astronboy, i take it you were referring to getting *just* the upper CR cut if i want to bolt it...? if i were going the cardstock route i would definitely back it up (zippy's suggestion) with at least a single .5" x .5" square behind the eye bolt along with epoxy.

but i was thinking...1/8" or 1/4" tubular kevlar wrapped around and epoxied to the base of the MMT, running up through the slit of the upper CR to just below the lip of the BT (to prevent zippering) would never really need to be replaced, so i'd avoid the eyebolt on CR method entirely. correct me if i'm wrong. very strong, heat resistant and it would last. and everything above the chute protector would be completely fine.

-RSE

#### astronboy

##### Well-Known Member
I have not used tubular Kevlar, but I have used the 1/8" 400# test braided Kevlar from BMS. I always do the 'wrap around the mmt' method.

#### RocketSmokEater

##### Well-Known Member
so here are 2 of my v-2 fins thus far. these things are a b****! anyway. no filling foam. nothing inside as skeleton. just plain old plastic sheets aligned and sanded as perfectly as possible.
i used a bit of "space-age" plastic sheet welder (instead of plastic cement) via a brush on as much of the overlapping surfaces as possible, then sanded but left small overhang for security. they seem pretty strong...how do they look?

anyone suggest how to fill the small little holes you see that i created via push pins thinking it would help keep the two pieces aligned for gluing? (suggestion off EMRR somewherem, but tape carefully placed works!). also, on one of the vanes i was trimming a bit too much and accidently opened a small gap in the plastic - doh!! how bout bit of epoxy to fill with some tissue paper of some sort, will that work?

-RSE

ps - still thinking bout mounting the "antenna" wood dowls in fairing exits...

#### sandman

##### Well-Known Member
RocketSmokEater,

They look fine.

Go to your local hobby shop (If you have one) or actually...Wal-Mart and Meijer carry it, and get some model car "contour putty"

That's whatI used on my original Maxi-V-2 way back in the 70's and it's still holding up just fine!

Use it to fill your hole AND to make your fillet where the fin glues onto the boatail.

Mine has over 50 flights on it with only the occational minor crack from hard landings, easily repaired.

The brush on liquid plastic cement works great for fixing the small cracks when they occur.

sandman

#### Stymye

##### Well-Known Member
the fins look good
squadron putty from a hobby shop or bondo spot putty from the automotive shops would help fill the holes and gaps..

#### RocketSmokEater

##### Well-Known Member
thanks sandman and stymye for your replies! stymye, are you Andy Hobbs by any chance? if so, you're the one with the orange and black V-2 modified with the alarm beeper, right? and you're the "A.H" who suggested the push pin idea i read about.

so had change of thought: instead of stock v-2 rings sandwhiched WITH perfectly duplicated custom-cut cardstock stock rings i made (1/8" total thickness together), i thought maybe to JUST use the stock rings with custom-made 1/16" balsa strips that glue under the upper CR and as a unit mounted between the MMT exterior and the BT interior length....for the lower CR same thing, but strips glued just above it toward the NC (all this is inside that sealed cavity between both CRs). the balsa wood cut in 1/2" long strips by whatever that interior MMT to BT distance is....yielding fairly lighter structure and potentially stronger....? (this idea was from a Tim @ Apogee).

just getting some opinions. thanks.

#### RocketSmokEater

##### Well-Known Member
thought to share this little "quick invention" with everyone. nothing very complex or anything, but being new to rocketry with new experiences, i thought i'd enlighten. the MMT/stuffer tube is very long on this rocket as you all may know (about 14"). getting glue in there at the 3.25" mark for the engine block is quite a challenge (i used my finger carefully), especially when trying to avoid getting glue anywhere in where the engine will go (of course you can wipe it up quickly if you see it). so after putting in the engine block using the yellow spacer tool, i wanted to reinforce the stuffer tube side of the engine block, and that distance is at least a foot or so down the tube. so i made a little scoop-like spatula using a piece of flexible cardboard taped onto a long metal rod to insert into the MMT (in level position initially). then when the tool reaches the engine block, just pull back a tiny bit and tilt the tube/spatula tool while *slowly* rolling it to get the glue in between the ring and MMT. i used Elmer's Pro Bond wood glue which is fairly runny. at the same time have an engine in there or some kind of block covered with some tissue or something to protect the engine and the compartment from glue.

am i genius, or not really?! ;-)

wood glue is excellent with wood-2-wood or paper-2-paper, but does anyone suggest dripping some epoxy over that wood glue coat on the engine block for extra security? i'm thinking of using wood glue for the CRs to MMT assembly as well (sinks into the fibers and holds), but definitely epoxy for plastic fins to plastic tail cone.