Modified Competitor 4 Build Thread

You were absolutely correct in assuming the J-460T for a first test flight....that is what I used to easily see all the events. It went 1890 on that motor .
I have not flown a K-700 in thus rocket, however I have flown the K-1050 single use to an altitude of 8860. They should be close though judging by the total newton seconds.
K700 2400n/s
KBA K-700 2560ns
K-1050 2560ns
That being said the KBA- K-750 flew the same configuration to 9001 as I have said earlier but only cost 112.00 vs the k-700 at 150.00 and the K1050 at 250.00
The K-550 costing 100.00 sent it to 5640ft.
So if you run the numbers cost wise, the most bang for the buck is easily the KBA-K750 at only 12.00 more than a K-550.

For my drogue side I use 35ft and the main side the same, but I use 2 mains, a 54 PML and a 72 spherachute, when I am drag racing. Just to make it easier to spot and follow my rocket out of the crowd. I also use a 96 topflight when flying solo. that thing is really overkill, it comes in so slow.I have a smaller topflight that I have used 72 that seems just perfect, I know it doesn't make sense but it comes in much much slower with that TF chute than when usung 2n chutes. Let us know what yous weighs in at. Mine is 13lbs on the dot ready for flight 2chutes, without motor.

Sure thing! I went with a rocket rage 30, probably will be a little on the slow side but thats not always a bad thing and it packs very small...

Its rated for 22fps at 30 pounds so probably will come down at 15-17fps, maybe a bit less.... with an M. With a J460T its going to come down rediculously slow! So yeah J460T, then an L1400 skid, then probably an M1315. Wonder how much height Ill get out of the skid, its a large L I believe because it goes in the 75/6000 case.

I am going to check out the store but I have decided I want to try some of the metallic paints from Duplicolor. Ill have to see what they have but I may do metalic (it has sparkles) red airframe with a shiny black cone and fins, black will look REALLY nice on the conical cone with the natural metal colored aluminum tip... And I think mixing a standard paint and a metalic will look real cool as well.

May be a few days before we get any more pics but the next pics will be of the bulkplate being glued in whenever I get it made (could be a week or so) but before that some pics of the filler being applied to the slots and fillets as well as the rocket all ready to go for primer... Ill be priming with duplicolor high build, then some of the regular duplicolor primer. Also some pics of the CD3 soon... Tom is going to drop it off at my house soon. That will be a fun toy to play around with!

Did some sanding, mostly just getting epoxy drips etc... off and working the fillets a little... I also sanded the seams off the conical cone. I think once the aeropoxy filler comes it will be a night for application, and one more night to sand it mostly off... If that first appliction is enough it will probably be one more night off sanding till everything looks just right for paint... That stage of sanding will be 150-180 grit, then after the filler primer it will get 180-220. Then the "standard primer" and 220-320, and a finish sand with 400 grit. Then its paint, 800 grit, clear, 800-1200 grit, polish and wax! I think I am going to start by painting the cone and upper tube for your guy's viewing pleasure, because it may be a week or two before the lower section is all ready to paint (filler is not here yet). And the upper tube and cone are smaller easier to prep/paint sections so its a good practice.

I have decided on metalic (sparkles in the paint) red for the airframes, black nose cone, black fins and also their will be a 1" section of airframe glued to the alt bay coupler for switchs and vent holes which I will paint black... Should look REALLY slick...

How well will the high build filler primer will scratches? Like from 40 grit sandpaper... Their are a few on the fins from sanding and I am hoping it will fill them up completly no worries.

jraice,

The duplicolor high build primer will fill scratches okay but don't expect it to fill much else. I bought quite a few cans of it with the idea of filling the weave of the fiberglass tip to tip on my last bird and it didn't do as I expected. I had used it in the past with success on filling spiral grooves of cardboard tubes but it really had no effect on the weave. I have a feeling duplicolor is just an expensive krylon with maybe a little different formulation. There is very little info on the cans in regards to addresses but they are both made in the same city with the same zip code. They are compatible with each other. Duplicolor's clear is really nice. Do a couple of light mist coasts then one thicker coat and it will shine quite well.

For a good high build primer try kilz.

jmiller said:

The JB weld on the fins was overkilll.. The fillet between the top and second CR was overkill, the plywood CR's was overkill... The list goes on. Your method of building the fin can (extending the slots) made fin alignnmet, what, a "3 time job"?.. Like I said, the "how to classroom" on RP presents some very good building skills, be it for a L1, but I'm sure you'll learn something.

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What was he supposed to do? Use wood glue? This is a fiberglass rocket, and he used high temperature epoxy in an area that will encounter high temperatures. I think your definition of overkill might be different than everyone else's.

I admire jraice for taking the fins off 3 times and then admitting it on here. That takes a lot of guts. However, I credit him for taking the time to do things right and not settle for mediocre workmanship.

jmiller said:

That's what happens when you only build a few birds. You don't really develop the building skills to build things right, but instead build them strong. Others like you will cheer, but don't have the background to say "you really don't need to do that!" That's what's happened here - you got cheerleaders.

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Define "right" If you are building them strong and having successful flights you are doing something right. Its better to build stronger and then refine than build weaker and shred rockets until you get one to work. You are implying here that it takes experience to build rockets to your level. So tell me, how does one gain this experience without.....BUILDING ROCKETS?

jmiller said:

I offered some ideas, and each time was met by "That's wrong", but as you are a 17 year old, I can understand that reaction. You are, in real terms, a L0, that by your own admission, has only built 6 HP birds. If you build "like a tank", that'll probably fly ok, but building for the "bird" is a different issue. That's where the "skill level" is involved.. I hope the cheerleaders understand this point.

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In real terms jraice is an L2. Just because this is not recognized by a slip of paper and a $60 a year membership fee does not make it any less true. Did he do everything any other L2 flyer has done? Yes, except take the test which is the simple memorization of a few common sense rules that a chimp could pass.


What certification level are you? How many rockets have YOU flown. Since you are an expert lets see some of your rockets. I am sure they are all Carbon Fiber Minimum diameter rockets with no drag and no epoxy. Anything more than that would be overkill!

I agree with David, the simple fact is that a lot of the rockets flying today are not built for performance, they are built for fun. You can't come in here and say someone is doing everything wrong when in fact they aren't. Not everyone is building super high performance rockets.

Very well said, Ryan S. Especially the part about gaining experience from building rockets. I was about to say that, but then I noticed that you had posted it.

Ryan S. said:

In real terms jraice is an L2.

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Nope.. In real terms he's at best got a "jr cert" level... Your logic would hold for a 14 year old that drives, but doesn't have the $25 licence. Does the lack of a $25 licence mean he's still a licenced driver? I think not!

Ryan S. said:

What certification level are you? How many rockets have YOU flown. Since you are an expert lets see some of your rockets.

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Been a L3 since 2000. As far as number of HP flights, I'd put it between 100 and 150. As far as number of HP birds, I'd say 30-40. I also was a Prefect and section advisor in the past.

You may have also missed the point that I'm finishing (painting) a competitor 3 right now - same basic bird as being discussed here. Same parts, but smaller (only a 54mm MM).

As far as "pictures", I don't really have any, other than some from Nadine I got framed on the wall....

Guys guys guys!

Anyways GLR order (with my filler) has shipped. I may get the bullkplate cut and glued tonight if my dad has time to help me cut one out but Im not sure... Hope to pick up some paint soon and start getting the nose and upper tube done...

Going to get most of the line of duplicolor , filler primer, sandable primer, metallic and standard paint, clear laquer, and then Ill be doing rubbing compound and auto wax! Should look beautilful especially with that skid!

Rest of the thread...?

Huh?

Sheesh it took me all night to think of those comments! Then someone comes along and deletes them!

Just kidding...

Glad to see this thread is getting somewhat back on track....

Ethan

doing a fine JOB there Jraice!!!!!!!!!!!!!!!!!!!!

Aeropoxy light is here... Ill be putting that on in a few then posting some pics! Then tomorrow when I get off work Ill check and if its nice and dry Ill began sanding for finishing!


After the rocket is all paint ready that only leaves making and attaching the booster sections bulkplate, electronics bay design and build (and ground testing) and then a few small things like vent holes, rail guides etc... Top guide will go into the bulkplate, about 35"s up. Should be plenty high... Other guide will be near the bottom, most likely just glued.

Did 3 fillets and all the slots...

This pic shows 2 of them, I didnt go crazy but I got a nice layer... Should be fairly easy to wet sand with 150 grit...

Tonight I am going to sand these and the slots... Then Ill do the other 3, recoat these 3 if necessary and also most likely give the slots one more coat so I can make them melt right into the curve of the airframe!

This stuff is a pain to measure out and mix but once I got it (and rested my arm) it had a pretty nice consistency and I found applying it with a glove and really pushing it into the surface worked well.

View attachment P1010144.JPG

What are you using as filler?

Its aeropoxy light...

Tonight I am going to sand the 3 fillets and the slots... Then Ill do the next 3 fillets, recoat the slots (I dont think they are fully filled, very close though) and if needed recoat the first 3 fillets... It should look real nice!

Hey Jordan,
Just for a data point, I flew my Comp 4 today on a Kosdon L1860. I "overbuilt" it with epoxy (I even used fin fillets... go figure...) and it had no trouble as it got hammered to 7500 feet. It's tough being an immature kid flying Curtis' kits, lemme tell ya...




(ps don't tell anybody, but we hooked the clips up while the igniter was outside the rocket... and it worked!)

Reese, you crack me up, I want to come hang out with you guys stat.



PS Sexy pics. Teach Todd how to do that. I want awesome pics.

Here is another data point for you, from a senile old man with part- timers [comes right before altzhimers] who forgot to do his fillets. 9001 ft KBA K-750.....9001ft on a KBA 750. Oh I guess I already said that, didn't I? I can't seem to remember/. ........... By the way, Daveyfire....what does yours weigh?

I can add another data point:

16,000 feet on an AT M1315 (Mach 1.25 @ 4 seconds into flight)
used carbon fiber strips with the epoxy, foamed the fins, nice size fin fillets.

Thanks rockets magazine for getting the picture



I even got video


Hope any of it helps, if not, at least I got to brag

Gerald Jr.

Just another data point for all you stat & number crunchers out there:
I flew my Competitor 4 to 5,500 ft on a 5 grain 54mm white load a few years back( sorry no pics.. see NERRF 1 video K 784 near the end of the DVD for the flight video).

Does anyone or everyone use vent holes other than for the altimeter?

I go as so far to even vent the fin can. I've seen a L3 rocket blow out the panels in between the fin, but that was on a full scale ASP.


JD

JDcluster said:

Does anyone or everyone use vent holes other than for the altimeter?

I go as so far to even vent the fin can. I've seen a L3 rocket blow out the panels in between the fin, but that was on a full scale ASP.


JD

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I used one in my booster along with shear pins, just for good measure. I've seen too many overpressurize.

Here's my data point....
My Comp-4 on a 5G75 Ex M of mine.
Not the highest or fastest - just had the data handy.
Shows Mach 1.25 and nearly 44G's.
No overbuild - actually "under" - I used a phenolic motor mount and ply CR's. No extra fiber or carbon. Just good TTW fin attach with Locktite 120HP.
I do foam all my fincans to provide additional damping against flutter.

rocketkyle said:

I used one in my booster along with shear pins, just for good measure. I've seen too many overpressurize.

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Exactly! Why not include a vent hole?

Wow! Look at all of these ridiculously overbuilt Competitor 4s flying totally successfully on awesome motors, by many successful and experienced rocketeers! I NEVER would have imagined so many would work...

(Nice flights, all. I wonder how many of these things Curtis has sold? It's a KILLER kit...)

gtm3323 said:

I can add another data point:

16,000 feet on an AT M1315 (Mach 1.25 @ 4 seconds into flight)
used carbon fiber strips with the epoxy, foamed the fins, nice size fin fillets.

Thanks rockets magazine for getting the picture



I even got video

Hope any of it helps, if not, at least I got to brag

Gerald Jr.

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Excellent brag too, wow!...what a nice flight, thanks for sharing!! 10,000ft more than my highest flight.

Johnnie

freda said:

Just good TTW fin attach with Locktite 120HP.

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Overbuilding!!!

jmiller said:

Overbuilding is a good thing for those that want a merit badge and don't care about the real science of the hobby.

Build what's needed, as you might get a good flight with "overbuilding", but do you have clue why?

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Do I have a clue why? Yes - because it was fun. This is, after all, a hobby. Rockets are "fun". Building rockets is "fun". I don't get paid to do it, I actually pay other people so I can do it! I'm not doing research on materials or aerodynamics or fluid mechanics. I'm building something to last so that I can fly it over and over again and not worry about it shredding or crashing (and possibly hurting someone in the process). I'm making sure that I don't have to take more money out of my bank account to replace a rocket that could have been saved by a stronger build technique. I'm building a rocket with my kids to bond with them (is that bond overbuilt, I wonder? I'm using an awful lot of adhesive there...), and delighting in the joy and wonder in their eyes as they track the rocket they helped me build mounting to the skies, and the excitement they have as they help me carry it back. It's not about the science involved - I get that at work. It's about having fun, being safe, and growing. He's overbuilding - so what? It's not YOUR rocket! As long as it's safe and can pass an RSO inspection, what's the difference? It's HIS rocket, HIS money, HIS build.

Well said Mark

rocketkyle said:

I used one in my booster along with shear pins, just for good measure. I've seen too many over pressurize.

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for the competitor I used 2 vent holes (in the drogue and main sections) along with shear pins.

https://s5.photobucket.com/albums/y174/gtm3323/?action=view&current=68633895.flv

Thanks guys! Well its still lots of finishing work right now... Played around with 150 grit on the filler, seems to be the best grit. The slots are pretty good, as are the 3 fillets I already covered with filler. Tonight I hope to recoat all of them and coat the remaining 3 slots... Hopefully that will be all I need but the 3 I havent done yet may also need 2nd coats to fill all the small low spots...

Anyways it looks really nice, after I get the basic shape done in the filler its gonna be a lot of 220 grit wet sanding to get the transitions smooth and make sure there are no bumps, and to clean up the fins etc...

This weekend I may start painting the nose cone and upper airframe, or atleast get some primers on...

I am really excited to see how these fillets look and how the paint looks! I usually just do 220 grit, primer, paint and clear... This time though Ill be doing a lot of new techniques and hope for an awesome finish...

Tom will be dropping the CD3 off eventually and that should make the begining of alt bay construction.

The tray will have the MC2, MAWD and GPS all together and will be interchangable between this rocket and my dads L3 bird, a 7.5" PC Patriot.

What altitude do you guys think I should expect from the AMW L1400? Its the skid load for the 75/6000 case. Ill have to check again but last I remembered, I dont have a rocksim file for it...

For those other flyers with Comp 4's... What lengths of harness's did you go with? I am thinking 30-40' drogue (will be drogueless) and then around 25' for the main. Its more then I usually do with 4", even 5" birds but given the weight of this rocket I think a bit more harness would be good...

And Ill be using 9/16" TN, havent decided on mil spec (lighter, packs tighter) or climbing spec (stronger, heavier, packs in a tad bit more area). I am thinking Ill consider getting some harness's with loops sewn in, because with the CD3 I shouldnt have to worry about burns, or having to replace harness's... Plus they are pretty neat and handy.