Hey - I'll gladly fly a W9 egglofter, and I'll guarantee egg survival too. It won't be next month, but I'll do it...

The problem would be that I'm not sure I have electronics that will handle it - my R-DAS only has an accel sensor good for 50 gees...

R-Das???? Xmas gift? Sweet, next I'll be hearing GPS and all the trimmings. 8)

I think someone should give Jim A a call. How many of us have Missile works altimeters. The achilles heel is the cap. If that can be partially potted, and not void any warranty, I'll bet the Missile works with the thru hole construction is good to well beyond 50gees. By the time a 38mm rocket egg lofter has the egg and cushioning whatever, I'll bet the gee loads are not much more than 50--thats part of the beauty of this competition. If you're worried can always build a 5 # brick
JS

Yep, R-DAS tiny as my xmas gift this year. I was really happy when I opened the wrapping and the package said it was from the Netherlands 😀 No GPS and trimmings yet, though telemetry would be awesome...

I wonder if it could go beyond 50 gees without damaging anything? If so, I could set the deployment on a timer instead of on apogee detect, and it would work fine (G-switch sensing only needs 0.25 sec, so it would work with W9). It's got 2 axis accel plus baro, all sampled 200 times a second for up to 29 minutes, so it's a wonderful little unit. 4 outputs too 😯 The project possibilities have been running through my mind since getting it 😀

Chris,

The R-Das is still the state of the art on several dimensions, but pricey! But hey you deserve it. Get the folks to throw in a trip to Amsterdam on grad, and you'll be in for a real treat. I wouldn't fly it unless you're really fixed on measuring gees. Just do an estimate and baro deploy.
J

Heh...

It would be the altimeter of choice for this contest (and of course I'm flying it). Honestly though, I'm more concerned about the NAR events for competition than the eggloft - I think that some of the events in the competition will be significantly harder than the H999 eggloft will be. We'll see though...

As present there is no competiton, but I think it would be a fun tack-on for MHM. I'm gonna fly a feasability in feb with a 2.6 inch payload section on a 38mm booster, MW altimeter.
J

I'll look forward to frying up the aftermath for a late prarie breakfast 😀

I'll look forward to frying up the aftermath for a late prarie breakfast 😀

Hey you can have breakfast but, here's the deal, if I do recover the egg intact, I get a photo op with egg on your face that I can submit to TRF 😛
JS

Sounds good, it would be worth it to see an egg survive a W9 load. Should be fun to watch, good luck!

I've got a system worked out, and I think it should survive (after some feasibility drop testing on the deck just now 😆 )
Heck - I may even spring for 54mm W9 😯

Just did some more drop testing outside for my latest method of egg-protection - got up to at least a few hundred gees impact (15 foot drop onto concrete). Something completely unexpected happened - I cracked the tupperware, but the egg survived. I think I have my method of containment figured out 😀

Also, if it's just for fun rather than as a contest, I'll go for the J1999 instead - my egg can handle it 😯

EDIT: just cracked open the egg - stunningly, after an impact of at least 350 gees, possibly more, the yolk was 100% intact.

EDIT #2: After more calculations, it would appear that it actually withstood an impact acceleration of around a thousand gees, though admittedly only for about a millisecond

How did you figure the G load? Accelerometer and a computer data acquisition system?

Warren

Nope. Simply knowing the speed at impact and estimating the distance that it stopped in based on the amount of deflection needed to cause a crack of the kind observed in the tupperware container. Turned out to be about a sixth of an inch to stop from 9.6 meters per second to zero. That's about a thousand gees. Even if it were to take a half inch to stop (MUCH longer than it really could have), that's 360 gees. Basically, it's far more acceleration than the W9 would create, and 1000 gees seems the most accurate estimate I can make with the current information.

What's the math involved in this? Show me the formula since I must admit to forgetting all that stuff I learned in college - I finished engineering school (at least the ME portion) before you were born.

Warren

I used the time-independent acceleration equation, V(f)^2-V(i)^2 = 2ad

In this case, after a fall of around 15 or 16 feet (around 4.9 meters), the velocity works out to be right at 9.8 meters per second, with a fall time of 1 second. The impact distance is around 1/6 of an inch, which is 0.0042 meters. So, we get (0)^2 - (9.80)^2 = 2*(a)*(0.0042)
This simplifies out to -96.04 = .0084*a
Divide both sides by 0.0084 and you get an a of 11,433 m/s^2. Divide this by 9.8 and you get 1167 gees.

(Apparently, AP physics is good for something after all 😉 )

Checked out CRASH's discussion on NCR's NAR event. The E booster glider seems to be getting a good response. But the G Super-Roc seems to be getting a bad response because of safety. Does anyone agree or disagree with this? While you can't use fiberglass tubes, you CAN glass paper tubes. Dale, if you read this, what are your thoughts? Joe, Warren, safety? Sending a spiraling, collapsing G into the flight line, even if pointed away from the crowd, is a possibility. We can certainly start whittling this down and dropping the larger events, if need be. Since not many have responded, there is still the option to make this a totally kid NAR event.