After downloading the plans for an Estes Sprint, I made it! It only took about a month but I nickle and dimed it to a final finish. I'm hoping to fly it tomorrow but it depends on the weather. The colors I chose are also the colors of my favorite football team....The Redskins. I just hope it flies better than the Redskins are playing this year.
Sprint Clone
- Thread starter carldoc
- Start date
Help Support The Rocketry Forum:
flying_silverad
Well-Known Member
- Joined
- Jul 23, 2002
- Messages
- 3,168
- Reaction score
- 5
- Joined
- Jan 17, 2009
- Messages
- 15,470
- Reaction score
- 237
The sprint has always been one of my fav rockets of all time. Mine isn't a clone though, I built it in the early 70's (if i recall correctly).
I painted her maroon with a sea green nose. After 30 years and over 400 flights, she ain't pretty, but she sure is proud...
Here a pix of Vern Estes and I after Vern launched her on her 401st flight at NARAM-45.
https://fliskits.com/photo_album/naram-45/images02/sprint01.jpg
I notice that you painted one fin to match the nose, in contrast to the rest of the rocket. I don't know if there is a name for this painting scheme but i love it and have used it for years, especially on 3-fin rockets. *Beautiful* job!
OH! and welcome to the forum too!
I painted her maroon with a sea green nose. After 30 years and over 400 flights, she ain't pretty, but she sure is proud...
Here a pix of Vern Estes and I after Vern launched her on her 401st flight at NARAM-45.
https://fliskits.com/photo_album/naram-45/images02/sprint01.jpg
I notice that you painted one fin to match the nose, in contrast to the rest of the rocket. I don't know if there is a name for this painting scheme but i love it and have used it for years, especially on 3-fin rockets. *Beautiful* job!
OH! and welcome to the forum too!
Thank you for the complements, guys. I admit that I'm not the greatest model builder but, I took my time, and used sanding sealer to give the nose and fins a glass like finish( I never used it before but as we get older we get wiser... I think ). I used Krylon spraypaint to finish it. The sprint was one kit I never attempted as a kid. The tapered end "scared" me off but, I always liked it's lines. I'm glad that I found Jimz's site for making clones. I'm going to attempt a few more clones including the very first rocket my Dad got me....the Estes Sky Hook.
Jim, over 400 flights! I would say you got your money's worth. How do you keep the tube from falling apart from all those flights?
Jim, over 400 flights! I would say you got your money's worth. How do you keep the tube from falling apart from all those flights?
Fore Check
Well-Known Member
- Joined
- Sep 24, 2010
- Messages
- 4,263
- Reaction score
- 9
Very nice!
I wonder where they get the claim that the Sprint will go to 1600 ft? I just this rocket together on RSim and the best I can get is about 1260.
I wonder where they get the claim that the Sprint will go to 1600 ft? I just this rocket together on RSim and the best I can get is about 1260.
- Joined
- Jan 17, 2009
- Messages
- 15,470
- Reaction score
- 237
A goodly percentage of the body tube is soaked in CA... It is all original except for the shock cord, launch lug and streamer.
Speaking of JimZ's site, i have someone looking to order a set of decals from him but i've lost his email to send an order....
as for the Estes Sky Hook, that was *my* first rocket too, back in 1963!
It is all original except for the shock cord, launch lug and streamer.Speaking of JimZ's site, i have someone looking to order a set of decals from him but i've lost his email to send an order....
as for the Estes Sky Hook, that was *my* first rocket too, back in 1963!
mikeyd
Old Rocketeer
- Joined
- Jan 17, 2009
- Messages
- 902
- Reaction score
- 231
Jim, go to this site and click on the "big yellow banner" that says "E-Mail Jimz" https://www.dars.org/jimz/rp00.htm or just try
[email protected] <[email protected]>
Happy Flying!
Fore Check
Well-Known Member
- Joined
- Sep 24, 2010
- Messages
- 4,263
- Reaction score
- 9
Changing the simulated launch altitude to 6000 ft only gains 120 ft (to a net 1380)
vjp
Well-Known Member
- Joined
- Jan 23, 2009
- Messages
- 1,487
- Reaction score
- 0
Perhaps the Cd that Rocksim is calculating is a bit conservative? I can get 1600 feet (from a 6K ASL launch) with a manual Cd input of 0.48. It's possible the thrust profile in the ENG file for the C6-7 is a bit off, too. I know the D12 and E9 profiles in the Apogee-supplied ENG files are WAY off.
As a real-world example, I got a predicted altitude of about 635 feet (on an A6-4) for an 18mm competition model I flew a couple of years back. The actual altitude was tracked to 734 feet. I think Rocksim had been over-cautious on the calculated Cd. Of course, the actual motor could have been 'hotter' than the ENG profile for the A6-4, as well.
All-in-all, Rocksim is great at putting you "in the ballpark", but real world scenarios can vary from simulations substantially.
As a real-world example, I got a predicted altitude of about 635 feet (on an A6-4) for an 18mm competition model I flew a couple of years back. The actual altitude was tracked to 734 feet. I think Rocksim had been over-cautious on the calculated Cd. Of course, the actual motor could have been 'hotter' than the ENG profile for the A6-4, as well.
All-in-all, Rocksim is great at putting you "in the ballpark", but real world scenarios can vary from simulations substantially.
teflonrocketry1
Well-Known Member
- Joined
- Jul 31, 2011
- Messages
- 1,627
- Reaction score
- 7
When I run the Sprint simulation straight up using the RockSim version 7 standard day conditions I get 1500 ft AGL on a C6-7. I let RockSIm calculate the Cd at the time of launch and used the RockSim equations and 0.25 inch motor overhang. Check your settings, especially your simulation resolution in sampes per second, make sure it is greater than 800!
Bruce S. Levison, NAR #69055
Bruce S. Levison, NAR #69055
