Estes Honest John Tips

Introduction:

This document contains PGI (previously given information) about building and flying the Estes Honest John model rocket that was originally posted to the rec.models.rockets news group by a number of people.

Comments are welcome.

Disclaimer: Free advice is often not worth what you paid for it.

Sven Knudson
sven@ninfinger.org

Engines/Motors:

jsivier@ux1.cso.uiuc.edu (Jonathan Sivier)
You don't even want to use an E15 with the plastic fins. We had a launch this weekend and someone launched a Maxi Honest John with an E15 and the fins tore right off.

soc1070@vx.cis.umn.edu (Tim Harincar)
I think the shredding you described was due to poor construction. I have flown a Maxi Honest John on an E30-10 and had a great flight. Really! I have a bunch of witnesses...

leer@fc.hp.com (Lee Reep)
I saw an Honest John fly on F14, and it was spectacular. I assume it was stock except for 29mm motor tube.

I also upgraded the motor tube [on my Honest John] to 29mm for F14 Black Jacks. These are really nice motors for big Estes stuff like the Honest John or Saturn V.

konrad@netcom.com (Konrad Hambrick)
The first flite on an Estes D12-3 was slow and majestic and peaked at maybe 100 feet and the chutes popped just past apogee. The only problem I had was a couple of shroud lines pulling free (I had used the 'old style' tie-a-knot-under- the-tape-disk method )-:

The second flite on an Aerotech E15-4W was scary ! The rocket apogee'd at about 250 feet and it took *forever* for the chutes to pop (I timed almost 5-seconds of delay). The nose cone chute pulled two shoud lines but landed OK. However, the main chute melted shut and needless to say, two of those wimpy plastic fins were trashed.

[After reconstructing the fins (see below)], those fins are now *solid*. The rocket still weighs 14 oz.and I flew it again on an E15-4W last Sunday. This time it hit 360 ft! Quick, gimme one of them F24-4W reloads ;-)

Anyhow, seems like a lot of work went into flapping those plastic 'wings' and now, I wish I had replaced the 24mm motor mount with a 29 MM one, like Mark and Lee discussed ;-)

jdunbar@slee01.srl.ford.com (Jon Dunbar)
Use composite motors! Estes black powder D's and E's spew far too much molten residue into the inside and outside of the plastic boattail.

Motor Mounts/Reinforcement:

Roger.Wilfong@umich.edu (Roger Wilfong)
Back when this was a regular kit, FSI used to sell a motor mount kit to allow you to use their motors in it. Given that the body tube is BT-80, you should be able to order LOC, Aerotech, THOY or other 2.6" centering rings and a piece of 29mm motor tubing to mount 29mm motors (E-H) - although you probably don't want to go past an E unless you do something to strengthen the vacuformed styrene fins. You should be able to use an Aerotech E-15 in the stock mount - although you might want to replace the motor tube with a thicker 24mm motor tube for longevitity. Another light weight addition if you're going to use high _thrust_ motors is to add a few triangular gussets between the motor tube and the cardboard centering rings - looks like this:

            _
           | |
        ========= - centering ring
         \ | | /  - gusset
          \| |/
          /| |\
         / | | \  - gusset
        ========= - centering ring
           |_|
             motor tube

The gussets can be balsa with the grain running on the diagonal.

jdunbar@slee01.srl.ford.com (Jon Dunbar)
Don't put the engine hook in the model (if you are converting to 29mm engine... it flies more realistically and true to life on a F14!)

leer@fc.hp.com (Lee Reep)
I'm building mine with a 29mm motor mount. I replaced centering rings with plywood ones, and the body tube with LOC 2.6: tubing. Well, I am using the nosecone, tailcone, and fins. :-)

Fins:

soc1070@vx.cis.umn.edu(Tim Harincar)
I cyano'd the exposed edges of the fins so that air wouldn't get between the halfs and split them. I remember I used liquid plastic cement on the root joint, with white glue as a filler/ fillet when I originally built it.

Looking back, I would have made new epoxy fillets on the fins, which I will do if I ever fly it again.

rcktjim@aol.com (Rckt Jim)
Others have also found the fins to be flimsy. I don't know if the original edition was the same way or not.

The rocket lands on the fins and cracks (or so was the experience of one club member).

One suggestion was to fill the fins with something, like that expanding foam in the spray can (or will that expand too much and make the fins bulge out?). [Create vent holes to allow the foam to expand without breaking the fins, SK] Another might be just to run heavy fillets of epoxy along the inside of the fins or insert a balsa form.

billspad@aol.com (Bill Spadafora)
They'll bend and/or break on a reasonably hard landing. If it's not too late, you might want to put in a stiffener. After seeing others fail, I plan to put a piece of basswood inside the the fin diagonally down to the lower tip in mine when I finally get time to finish it.

leer@fc.hp.com (Lee Reep)
The problem is the thin styrene. It came unbonded at some points, and when I resealed, two fins warped slightly. I got so disgusted a ripped them off. Guess I'll add to winter project list. :)

I made long thin "diamond" shaped pieces out of popsicle sticks, ran nails thru them to act as anchors (like rebar) back into the tailcone. I reinforced the tailcone with a homemade plywood centering ring, with wood strips inside that those nails pass thru. These will be anchored with epoxy. BTW, the nails were cut off so that they would project thru the tailcone, thru the other wood reinforcement, and have a stub showing to grab the epoxy.

If I did it again, I'd fill the fins with something to reduce their flex. However, they feel solid, and should survive the added thrust. I plan to fly on F14 Black Jacks.

If the model will be display only, then use stock fins. I'd not recommend anyone use them for flying, even with the "beefing up" that I did. They are just too difficult to build.

jdunbar@slee01.srl.ford.com (Jon Dunbar)
Well, the directions for attaching [the fins] with liquid cement are just fine for the kit. You have another way though; I recommend not using the 24" chutes that come with the kit. Use larger chutes (36"), or just pack a larger single chute in the model. I have flown my Honest J, and recovered off of cement; with just scratches to the paint, fins hold just fine with the cement. You should use the cement in moderation, too much and you can warp the plastic.

ELDERGD%CWI@cwmail.usafa.af.mil (GREGORY D. ELDER)
I attached the fins to my Honest John with CA and then used Epoxy for fillets. I haven't flown it yet, however.

konrad@netcom.com (Konrad Hambrick)
I CA'd two sheets of 1/8" balsa to either side of a sheet of 6 x 12 x 1/16" birch aircraft plywood:

      balsa    balsa
         :  ||  :
         :  ||  :
         :  ||  :
                     ( make two of these --
         :  ::  :      you can produce two
                       fins per 6 x 12" sheet )
         :  ||  :
         :  ||  :
         :  ||  :
           birch

Then I made the fins with 'naked' 1/16" plywood tabs by cutting away the balsa along the root edge like so:

          ___                          ->| | <- 1/16" naked | |\ balsa- .|. birch | | \ birch- | tab> |   |    \       balsa           |
         |   |      \  <- sandwich | | | \ | | | \> . | . <- 1/4" | | . \ | | | . \ | | | . | | |___| .| | |_______________| .|.

Anyhow, you get the idea. There is a full size, postscript drawing of the fin/boattail unit available. The hidden line work leaves a little to be desired but LaTeX (TeXCAD) does not do dotted lines :-( I also neglected to do an edge-on drawing of the airfoil but I did not need one to remind me of all that sanding I had ahead of me )-;

I made four copies of the pattern and cut them out along the motor mount-tab-fin outline. Then, I glued the pattern to the sandwich and prep'd the 'naked' tabs by cutting thru the balsa, down to the plywood along the boattail outline and chiseling it out.

After a week of sanding and sealing, I dremel'd some slots in the plastic boattail and epoxied the fins to the motor mount. The pattern shows the MM-tube slightly under-sized so you have to sand a little off the tabs.

Those fins are now *solid*.

horner@cdc.hp.com (James G Horner)
Well, I just started work on my Honest John this past weekend after having it sit in the closet for almost two years. I too thought the plastic fins were flimsy, but I didn't want to sand balsa or plywood into the diamond shape. So I built up fins from 1/64" plywood over a framework of 1/16" balsa. I used one of the plastic fins as the pattern for the plywood skins. Cut out the plywood around the outside edge of the fin, and score it at the facet joint. The dimensions of the balsa diamond at the base of the fin can also be obtained by measuring the plastic fins. The framework consists of a balsa diamond at the base and a balsa trapazoid running from the base to the tip along the facet joint. The tip ends were filled in with scrap balsa and Elmer's wood filler. The resulting fins are much stronger than the plastic fins. Also, in my kit, the plastic fins seem to be bowed somewhat on each facet. My scratch built fins don't have this problem. It took me about 2 minutes to build each fin.

I drilled a series of holes in the boat tail and in the base of each fin and mounted them with epoxy. The epoxy went into the holes to form nice rivets. I've used the same techniques on a scratchbuilt Nike-Tomahawk and on a scratchbuilt RAM-B3. I haven't had any problems yet with these.

I really recommend this method. It can actually be faster to construct a fin this way than to sand balsa to the correct shape. It's also much easier to obtain the correct fin shape this way. Fins made this way are fairly light, and seem to be stronger than balsa. Ditch the plastic fins and make your own!

Section 4.1.4 of the FAQ also describes this method.

Other Construction Tips:

soc1070@vx.cis.umn.edu (Tim Harincar)
I added epoxy to the C rings of the motor mount using a long piece of dowel. And I also added more shock line and a nylon chute. (I tied the nose and body together). I also epoxied the launch lugs on.

jdunbar@slee01.srl.ford.com (Jon Dunbar)
Really work hard to secure the launch lugs!!! I really beefed them up with several coatings of epoxy.

Use a hole punch on the motor band. DO NOT FOLLOW THE ESTES INSTRUCTIONS AND TRY CUTTING THEM OUT WITH A KNIFE! Believe me, it would be scale like (the kit is really sport scale anyway) but it will look a 1000 times better!

leer@fc.hp.com (Lee Reep)
The LOC tubing 2.6" is basically same ID as BT-80, and a little larger in OD. The nice thing about the Honest John is that the shoulders of nose cone and tail cone are slightly larger in diameter than body tube, so the small difference does not show.

You could reinforce the Estes tubing -- I just happened to have LOC tubing, so I made the switch. I also mounted a piano wire loop in the top plywood centering ring to put a 10 foot elastic shock cord on, and will use a 30" nylon chute for recovery.

Another tip. I painted the area of nose cone under the spin rocket holes black before assembly. Just plug the holes with cotton swab before painting olive green. I used Dremel tool to drill out the holes, BTW.

horner@cdc.hp.com (James G Horner (transfered to HPL))
Hey, I also drilled out those [spin rocket] holes. Good idea regarding the cotton swabs.

Frank Burke modified his Honest John for high power and wrote an article (in PostScript) describing what he did for the Seattle Tripoli chapter newsletter.

Recovery:

soc1070@vx.cis.umn.edu (Tim Harincar)
I used a 24" cloth 'chute, and it was a really calm day, so the landing was exceptionally light.

Your mileage may vary.

jdunbar@slee01.srl.ford.com (Jon Dunbar)
I have found one method of increasing the survival rate of the model. throw away those Estes parachutes and use larger 36" or so chutes in their place. Try flying the model over grass!