Dr. Zooch Saturn V ?

Hi guys, this is my second Dr Zooch Saturn V and for some reason that i cant explain after it leaves the pad it becomes very unstable and lawn darts. The fins are the correct size as per the temps so i don't think that's an issue. It tumbles around at 35-40 feet then lawn darts before ejection. Both launched on a c6-5, could it possibly be nose heavy? Weird both kits did the exact same thing and i know its not the kit as others have had great success with the V its got to be something i did wrong. my other Zooch rockets fly great just not this one.

thanks guys for any tips or help.

The first time I flew my Dr Zooch Sat V, I used a C 6-3 and it went unstable at about 25-30ft belly flopped and ejected.

On the next flight I tried a B 6-4 with much better results.

After several more succesful B 6 flights I tried a C 6 again and again it went unstable, I still don't know why.:confused2:

You likely need more nose weight. Good to know, as I just started building one myself.

I haven't had any stability problems with my Zooch Saturn V.
Both B6-4s and C6-5 engines have been used.
It's a personal favorite.

The Saturn V is pre-loaded with nose weight.
I'm sure Wes O. (Dr. Zooch) will chime in on this one.

I did a complete build on the Zooch Saturn V on the build blog:
https://modelrocketbuilding.blogspot.com/search/label/DZ Saturn V+
There's a few tips that's might help with your build.

Correct... if the rocket is going unstable, you need MORE noseweight, NOT less!

Wes will most likely chime in here pretty soon...

I've flown mine a lot on C6-5's and never had any problems whatsoever...

Later! OL JR

Thank you guys for the reply's. I also tried a b6-4 and the same thing unstable. lucky the ground was soft from the rain no damage at all and it was in deep twice lol. What would be a good weight source, sorry for the greenhorn questions guys still a little new to this.

thanks again...

maverick pro said:

Thank you guys for the reply's. I also tried a b6-4 and the same thing unstable. lucky the ground was soft from the rain no damage at all and it was in deep twice lol. What would be a good weight source, sorry for the greenhorn questions guys still a little new to this.

thanks again...

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The nose cone is pre-loaded with the correct weight for "stock" build, so you may have built a little heavy by adding a lot of glue or other things. Did you substitute something heavier for the Funky Glue Putty? That might have added weight at the back where you don't want it.

Adding weight to the back of a rocket will move the Center of Gravity (CG) backwards. If it gets too far back the rocket will fly unstable as you're describing.

Measure where your CG is by trying to balance the rocket on it's side, on the edge of a ruler or something similar. The balance point should be right at the CG. Measure that point from the tip of the rocket and let us know where yours is.

You can add weight to the nose by getting some modeling clay and pressing it around the eyelet screwed into the back of the nosecone. This will move the CG forward - the more clay you add the further forward the CG will go. This is NOT a case of "the more the better", because you'll also have issues if the CG is too far forward.

Perhaps HCMBanjo, Luke Strawwalker, or I will measure the Center of Gravity on our models soon and report back to this thread so you'll know where yours should be, and you'll know if you've added too much or too little weight. I'm at work right now or I would be happy to measure mine.

If you get your GC back to where it should be the rocket will fly stable again.

You can glue washers or pennies to the base of the LG adapter.

Does anyone have a design file for this model? That would help locate the CO so the CO position could be dialed in.

Mushtang said:

Perhaps HCMBanjo, Luke Strawwalker, or I will measure the Center of Gravity on our models soon and report back to this thread so you'll know where yours should be, and you'll know if you've added too much or too little weight. I'm at work right now or I would be happy to measure mine.

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Are we checking with the model fully loaded?
We should do it with a C6-5, wadding and parachute in place.



With all the nozzles and shrouds in the rear I took my C/G from the top of the BT-60 tube main tube, right below the large adapter.
My C/G point with wadding, parachute and new C6-5 was 3 13/16" from the top of the BT-60 main body.
You'll have to enlarge the picture to see the pencil mark on the C/G point.

The C/G was the same for two different Zooch Saturn V models, my frequent flyer and shelf queen. Both were loaded for flight.

Thank you guys...loaded with a c6-5 its at 4 inch from the top of the BT to the c/g mark.

The f-1 engines are just the string and paint. I didn't do a lot of detail to them and i used medium CA for most of the build. when i load a b6-4 the c/g is farther forward like Chris Saturn. But even with a b6-4 it was unstable.

thanks again...

hcmbanjo said:

Are we checking with the model fully loaded?
We should do it with a C6-5, wadding and parachute in place.

View attachment 184680

With all the nozzles and shrouds in the rear I took my C/G from the top of the BT-60 tube main tube, right below the large adapter.
My C/G point with wadding, parachute and new C6-5 was 4 13/16" from the top of the BT-60 main body.
You'll have to enlarge the picture to see the pencil mark on the C/G point.

The C/G was the same for two different Zooch Saturn V models, my frequent flyer and shelf queen. Both were loaded for flight.

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you mean 3 13/16? unless im looking at it wrong.

maverick pro said:

you mean 3 13/16? unless im looking at it wrong.

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Yep, you're right!
3 13/16" from the top of the BT-60 tube.
I've corrected my other post.

hcmbanjo said:

Yep, you're right!
3 13/16" from the top of the BT-60 tube.
I've corrected my other post.

Click to expand...

mines at 4 inch with c6-5 and closer to your mark with b6-4 guessing tail heavy as you guys suggested.
im going to make it as close to your c/g as possible and give it a try. will let you guys know if that works out or not.
i still cant figure out why it got so heavy in the tail section.
thanks again...

I don't have a Saturn V and I haven't gotten to fly my 1b yet, and I agree that nose weight could be an issue but how straight is the LES tower? If it is at an angle it could act like a forward fin and destabilize the stack by moving the center of pressure forward.

maverick pro....my Saturn V flew with no problems...but if I recall Dr. Zooch (Wes) indicates in the instructions not to "over build" this kit.....too much glue, epoxy etc. I pulled my old instructions and Wes states that if your cg is off by as little as a 1/4 inch she could go unstable. If you are anything like me..I always tend to build a battleship....probably not a good idea on this particular kit. That being said, my Saturn flew beautifully....lucked out I think!

MJennings....would love to see some pics of your 1b! The Zooch 1b is my all time favorite kit..plastic or rocket....she flies like a champ!

mjennings said:

I don't have a Saturn V and I haven't gotten to fly my 1b yet, and I agree that nose weight could be an issue but how straight is the LES tower? If it is at an angle it could act like a forward fin and destabilize the stack by moving the center of pressure forward.

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Chris...your Saturn V is just beautiful!! I always enjoy your builds! its always a pleasure to watch the Master at work!!

hcmbanjo said:

Are we checking with the model fully loaded?
We should do it with a C6-5, wadding and parachute in place.

View attachment 184680

With all the nozzles and shrouds in the rear I took my C/G from the top of the BT-60 tube main tube, right below the large adapter.
My C/G point with wadding, parachute and new C6-5 was 3 13/16" from the top of the BT-60 main body.
You'll have to enlarge the picture to see the pencil mark on the C/G point.

The C/G was the same for two different Zooch Saturn V models, my frequent flyer and shelf queen. Both were loaded for flight.

Click to expand...

I probably over built the first and second one. my SA 5 flys great, the tower, nose, and fins are straight. going to try the nose weight and get it close to 3 13/16 and see what happens. If it does go unstable again i just hope it makes it through the lawn darting lol. I will try it out this weekend and let you guys know what happens. One more thing about the 1/4 inch c/g he states in the build. If you load a b6-4 it will be a 1/4 off c/g or more than it would be with a c6-5. Others have launched with the b6-4 without problems just curious as to why it still flys with that much of a change in c/g when the directions state it wont?

NJRick said:

MJennings....would love to see some pics of your 1b! The Zooch 1b is my all time favorite kit..plastic or rocket....she flies like a champ!

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I need to put up some final pics but here is the start of the build
https://www.rocketryforum.com/showthread.php?8715-Dr-Z-Saturn-1B-Stingray-and-Point

Mjennings! nice tower! I did something very similar...but you did it years before I did!

mjennings said:

I need to put up some final pics but here is the start of the build
https://www.rocketryforum.com/showthread.php?8715-Dr-Z-Saturn-1B-Stingray-and-Point

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What type of parachute are you using?

maverick pro said:

I probably over built the first and second one. my SA 5 flys great, the tower, nose, and fins are straight. going to try the nose weight and get it close to 3 13/16 and see what happens. If it does go unstable again i just hope it makes it through the lawn darting lol. I will try it out this weekend and let you guys know what happens. One more thing about the 1/4 inch c/g he states in the build. If you load a b6-4 it will be a 1/4 off c/g or more than it would be with a c6-5. Others have launched with the b6-4 without problems just curious as to why it still flys with that much of a change in c/g when the directions state it wont?

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thanks, I owe it all to Jim Flis and Peter Alway though, I just glued it together they did all the research and came up with the process

I have the jFlis Saturn 1b looking at me here...I bought it just to see what he does with it and that tower.

mjennings said:

thanks, I owe it all to Jim Flis and Peter Alway though, I just glued it together they did all the research and came up with the process

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Dr.Zooch said:

What type of parachute are you using?

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The stock chute in the kit. I have not had a chance to launch cause of the bad weather we have been having. Wanted to see what it would do with the new c/g location. on another note are you no longer producing the SA-5? I didn't see it on your site.
thanks...

maverick...I think he still sells the SA-5....it is on the apogee site https://www.apogeerockets.com/Rocket_Kits/Scale_Rockets?sort=&filter_id=13&alpha_filter_id=8

maverick pro said:

The stock chute in the kit. I have not had a chance to launch cause of the bad weather we have been having. Wanted to see what it would do with the new c/g location. on another note are you no longer producing the SA-5? I didn't see it on your site.
thanks...

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I seen it there also but didn't see it on his site. Figured it was no longer in production and i got really sad lol. It has got to be my all time favorite of the Saturn line or of any rocket.
thanks...

understand completely Maverick...I think I read somewhere that the SA-5 was Dr. Zooch's all time favorite rocket. It is a cool looking rocket! His SA-5 flies great too!

For me, I have always loved the look of the Saturn 1b...just a mean nasty looking rocket. The Zooch 1b (white tank version) is the best. his kit is my favorite kit, plastic or rocket. Just amazing what he can do with some pieces of card stock and balsa. I can't tell you how many of his 1bs I have built....but I can tell you this...I am going to build more!!!!

maverick pro said:

I seen it there also but didn't see it on his site. Figured it was no longer in production and i got really sad lol. It has got to be my all time favorite of the Saturn line or of any rocket.
thanks...

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Hey NJRick...the 1b is awesome and going to be on my to do list. Built one years ago but never got a chance to launch it. I have a shopping cart full of his kits ready to buy when the funds come in. my SA-5 flys great absolutely love it and plan to get a couple more to have on hand.

thanks...

NJRick said:

I have the jFlis Saturn 1b looking at me here...I bought it just to see what he does with it and that tower.

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Yeah it is neat sadly mine is going to remain in the bag for at least another year till grad school is done, but hopefully I'll have more workspace as we are moving shortly, and a hobby/craft/LEGO/rocket room is on the list of desirableness for the new house.