Got to try my Egg Finder this weekend

The Rocketry Forum

Help Support The Rocketry Forum:

SoCalChris

Well-Known Member
Joined
Dec 9, 2015
Messages
91
Reaction score
0
So I purchased and built an Egg Finder a while ago, and finally got to use it this weekend.

I flew a minimum diameter 38mm J570 to an altitude of 13,186' AGL (L2 certification flight). The Egg Finder tracked the entire flight, and I lost signal when it was approximately 300' above ground. The rocket landed 2.65 miles from the launch site, the Egg Finder took me to within 100' of the landing spot. By far the hardest part of the recovery was getting to where it had landed, without the GPS I would have never seen the rocket again.

If you're on the fence about getting one of these, or are questioning how well they work, don't. I was blown away by how well it worked, especially considering the price of the system. Great job to the designer! I will definitely be buying one of the new smaller ones and using it on all of my flights going forward.
 

OverTheTop

Well-Known Member
TRF Supporter
Joined
Jul 10, 2007
Messages
5,308
Reaction score
2,635
Location
Melbourne Australia
It is a great feeling to walk up to a rocket that has landed 3 mile away and completley out of sight. It is hard to describe, but somewhat like taking your ski boots off at the end of a good days skiing. :)

Until you ski, or put a GPS in your rocket you will never know...
 

Wayco

Desert Rat Rocketeer
TRF Lifetime Supporter
Joined
Mar 23, 2011
Messages
3,665
Reaction score
669
Location
Goodyear, AZ
If you take your receiver with you to recover the rocket, it will pick up the TX signal as you walk toward where the signal was lost. Makes that last 100 ft. easier. The RX will start beeping when it re-acquires the signal and update the rockets position. Walk right to it, it's that accurate!
 

soopirV

Well-Known Member
Joined
Sep 1, 2010
Messages
1,157
Reaction score
6
It is a great feeling to walk up to a rocket that has landed 3 mile away and completley out of sight. It is hard to describe, but somewhat like taking your ski boots off at the end of a good days skiing. :)

Until you ski, or put a GPS in your rocket you will never know...
That's a great analogy!
 

SoCalChris

Well-Known Member
Joined
Dec 9, 2015
Messages
91
Reaction score
0
If you take your receiver with you to recover the rocket, it will pick up the TX signal as you walk toward where the signal was lost. Makes that last 100 ft. easier. The RX will start beeping when it re-acquires the signal and update the rockets position. Walk right to it, it's that accurate!
That's pretty much exactly what happened. As soon as the receiver started getting updates, we stopped so I could put in the updated coordinates. As I was doing that, my daughter saw one of the chutes blowing around behind a bush.
 

KenRico

'Just the Tip'
Joined
May 31, 2011
Messages
2,727
Reaction score
40
So I purchased and built an Egg Finder a while ago, and finally got to use it this weekend.

I flew a minimum diameter 38mm J570 to an altitude of 13,186' AGL (L2 certification flight). The Egg Finder tracked the entire flight, and I lost signal when it was approximately 300' above ground. The rocket landed 2.65 miles from the launch site, the Egg Finder took me to within 100' of the landing spot. By far the hardest part of the recovery was getting to where it had landed, without the GPS I would have never seen the rocket again.

If you're on the fence about getting one of these, or are questioning how well they work, don't. I was blown away by how well it worked, especially considering the price of the system. Great job to the designer! I will definitely be buying one of the new smaller ones and using it on all of my flights going forward.
Very aggressive L2 Certification flight !

Well done !

Kenny
 

SoCalChris

Well-Known Member
Joined
Dec 9, 2015
Messages
91
Reaction score
0
Very aggressive L2 Certification flight !

Well done !
I wouldn't go that far... The shock cord snapped during the drogue deployment, so no L2 for me. Yet. Otherwise it was a beautiful flight.
 

Buckeye

Well-Known Member
TRF Supporter
Joined
Sep 6, 2009
Messages
2,715
Reaction score
529
I wouldn't go that far... The shock cord snapped during the drogue deployment, so no L2 for me. Yet. Otherwise it was a beautiful flight.
That is an L2 attempt with gusto! How was the up part? Those long skinny rockets with big motors can get squirrely.

Did you lose the sustainer after the drogue cord broke? I assume you found the payload section only, with tracker inside.
 

SoCalChris

Well-Known Member
Joined
Dec 9, 2015
Messages
91
Reaction score
0
That is an L2 attempt with gusto! How was the up part? Those long skinny rockets with big motors can get squirrely.

Did you lose the sustainer after the drogue cord broke? I assume you found the payload section only, with tracker inside.
Yes, I never found the sustainer (Or the motor casing that it contained :facepalm:). The cord broke between the drogue and sustainer, so I was able to retrieve the electronics bay with the flight computer, and the nosecone with the Egg Finder. The flight itself was pretty much perfect, very straight, no hint of instability.

[YOUTUBE]-p1mNjvxJ98[/YOUTUBE]

The rocket itself was beautiful too, I laser etched all of the fins. Hopefully someone will find the sustainer at some point, I'd love to fly this one again.

DSC_3078.jpg DSC_3071.jpg
 

Wayco

Desert Rat Rocketeer
TRF Lifetime Supporter
Joined
Mar 23, 2011
Messages
3,665
Reaction score
669
Location
Goodyear, AZ
I wouldn't go that far... The shock cord snapped during the drogue deployment, so no L2 for me. Yet. Otherwise it was a beautiful flight.
This is almost like Deja-vu for me. My first L2 attempt was with a scratch built 54mm minimum diameter rocket on a J360 Skidmark. Not quite as aggressive, but had a similar malfunction. My tubular nylon shock cord broke when the main came out at 700 ft. Recovered everything and flew it again at the next launch successfully. Since then, almost everything I build has Kevlar shock cord.

If you want to make your Eggfinder recovery even slicker, add a bluetooth HC-06 module to your receiver and link an Android phone with "Rocket Locator" to it. The phone has a map on it with a dot for your rocket and a triangle (arrow) that is you. Just aim the arrow at the dot and walk to your rocket. No GPS coordinates to transfer or transpose. When you get close, the map will automatically update to the new location.

 

SoCalChris

Well-Known Member
Joined
Dec 9, 2015
Messages
91
Reaction score
0
This is almost like Deja-vu for me. My first L2 attempt was with a scratch built 54mm minimum diameter rocket on a J360 Skidmark. Not quite as aggressive, but had a similar malfunction. My tubular nylon shock cord broke when the main came out at 700 ft. Recovered everything and flew it again at the next launch successfully. Since then, almost everything I build has Kevlar shock cord.

If you want to make your Eggfinder recovery even slicker, add a bluetooth HC-06 module to your receiver and link an Android phone with "Rocket Locator" to it. The phone has a map on it with a dot for your rocket and a triangle (arrow) that is you. Just aim the arrow at the dot and walk to your rocket. No GPS coordinates to transfer or transpose. When you get close, the map will automatically update to the new location.

This was a kevlar shock cord. Rated to 300# tensile strength. I did the math, that should have been more than sufficient. The only thing I can think of is either I grossly miscalculated the ejection charge, or there was a defect in the cord itself. If I had to guess, I probably miscalculated. Normally I would use stronger cord, but with this being MD, and the size of the motor, I didn't have room for something thicker. Live and learn :confused2:

I'll check out the Rocket Locator, that sounds interesting.
 

rharshberger

Well-Known Member
Joined
Oct 13, 2014
Messages
9,897
Reaction score
1,860
Location
Pasco, WA
One other thing is, was the edge of the airframe tubing chamfered a bit, FG airframes can have sharp edges and 300# Kevlar is pretty thin stuff, was it possible the Kevlar got cut during the apogee event.
 

Ccolvin968

Well-Known Member
Joined
Oct 11, 2016
Messages
314
Reaction score
0
Sounds like an awesome flight!
How difficult was the kit to build?
Did you have lots of soldering experience prior?
I did an eggtimer classic and just flew and got my L2 with it last Saturday.
Do you think it would be similar difficulty or harder?
 

ksaves2

Lifetime Supporter
TRF Lifetime Supporter
Joined
Nov 25, 2009
Messages
6,176
Reaction score
415
Location
Central Illinois
This is almost like Deja-vu for me. My first L2 attempt was with a scratch built 54mm minimum diameter rocket on a J360 Skidmark. Not quite as aggressive, but had a similar malfunction. My tubular nylon shock cord broke when the main came out at 700 ft. Recovered everything and flew it again at the next launch successfully. Since then, almost everything I build has Kevlar shock cord.

If you want to make your Eggfinder recovery even slicker, add a bluetooth HC-06 module to your receiver and link an Android phone with "Rocket Locator" to it. The phone has a map on it with a dot for your rocket and a triangle (arrow) that is you. Just aim the arrow at the dot and walk to your rocket. No GPS coordinates to transfer or transpose. When you get close, the map will automatically update to the new location.

Yeah, I did some tracking with some "hacked" Ham software and got the tracks shown in this thread: https://www.rocketryforum.com/showthread.php?137555-Eggfinder-Map-tracks.

I tried GPS Rocket Locator before it could cache maps and I was able to get a recovery of a completely out of sight flight, 8500', drifting to 1.66 miles away. North is up and I just followed the path to the last known position and re-acquired the signal to lead me in.
Used a Yagi handheld on the ground recovery and it certainly increases the ground footprint of the tracker. GPS Rocket Locator: https://play.google.com/store/apps/details?id=com.frankdev.rocketlocator&hl=en can cache maps for offline use but
unfortunately I believe Google maps locked the program out and it is no longer possible to even display the maps while online. The Open Source Maps work fine online and with caching so yeah, it was nice having a photomap to see that you likely
landed next to "that tree" and not in it, but OSM will still get you to your rocket. Better yet a map might give you an alternative route to get to your rocket onroad rather than triapsing across a field with obstacles.

I had a gut feeling this was going to happen with Google and as soon as GPSRL had the capability to store tiles, I furiously download my local town and two of my closest flying sites at a pile of different zoom levels with the Google maps.
I found out I was able to "lift" the maptiles off a Nexus 7 2013 and stick them on another device. 220mb worth at that.

Would be nice if the author, Francois, would re-do the program so it defaults to the Open Source Maps on startup and drop the Google maps if they're going to be ditzy about it. Kurt
 

mpitfield

Moderator
Staff member
TRF Lifetime Supporter
Global Mod
Joined
Jul 7, 2013
Messages
4,904
Reaction score
432
Location
Toronto, Ontario
This was a kevlar shock cord. Rated to 300# tensile strength. I did the math, that should have been more than sufficient. The only thing I can think of is either I grossly miscalculated the ejection charge, or there was a defect in the cord itself. If I had to guess, I probably miscalculated. Normally I would use stronger cord, but with this being MD, and the size of the motor, I didn't have room for something thicker. Live and learn :confused2:

I'll check out the Rocket Locator, that sounds interesting.
GPS trackers are pretty cool. My longest recovery was 3.46 miles from the pad, in the middle of a farmers field with 8' corn. I would have never found it without a tracker and directional tracking on it's own would have taken much longer. I literally plugged the last known coordinates into my car GPS, drove as close as I could, got out picked up the signal again and walked right to it. It is almost too easy!

What length was your recovery harness? I like a bit of extra length to help take out the energy. Also taping the harness in z-folded bundles can help with this.

Best of luck on your next attempt, and don't let this lesson put you off going for your round two cert flight with just as much gusto. When you have the most to lose it is the best time to put it on the line in my opinion.
 

SoCalChris

Well-Known Member
Joined
Dec 9, 2015
Messages
91
Reaction score
0
One other thing is, was the edge of the airframe tubing chamfered a bit, FG airframes can have sharp edges and 300# Kevlar is pretty thin stuff, was it possible the Kevlar got cut during the apogee event.
I don't see how it would have cut it, unless during the long descent it sat there and sawed through the kevlar on the way down at the tube rocked back and forth. That could have been a possibility.

Sounds like an awesome flight!
How difficult was the kit to build?
Did you have lots of soldering experience prior?
I did an eggtimer classic and just flew and got my L2 with it last Saturday.
Do you think it would be similar difficulty or harder?
The kit was fairly easy. I'd also previously built an Egg Timer Classic, I think that one was harder honestly. I don't have a huge amount of soldering experience, although I'm not bad at it. The Egg Timer was my first kit with surface mount components, the Egg Finder was my second.

GPS trackers are pretty cool. My longest recovery was 3.46 miles from the pad, in the middle of a farmers field with 8' corn. I would have never found it without a tracker and directional tracking on it's own would have taken much longer. I literally plugged the last known coordinates into my car GPS, drove as close as I could, got out picked up the signal again and walked right to it. It is almost too easy!

What length was your recovery harness? I like a bit of extra length to help take out the energy. Also taping the harness in z-folded bundles can help with this.

Best of luck on your next attempt, and don't let this lesson put you off going for your round two cert flight with just as much gusto. When you have the most to lose it is the best time to put it on the line in my opinion.
The shock cord on both ends was around 20'. It wasn't taped, but was put into a really loose slipknot chain to try to help disperse the energy.

This didn't deter me. Before the launch, my daughter asked what I'd do if we didn't get the rocket back (Which with the rocket and motor combination, I felt like that was a realistic possibility). I told her we'd go buy a new one, and try again. The first thing I did when we got back to the launch site was head over to Wildman West's tent, and bought a new kit (3" Punisher). We're now building that, and will hopefully launch it at RocStock next month.
 

SoCalChris

Well-Known Member
Joined
Dec 9, 2015
Messages
91
Reaction score
0
If nothing else, I learned a hell of a lot with this rocket. It was my first MD build. Also my first using dual deploy. First using a GPS. First confirmed to break mach (Although I suspect I've had 2 other flights break mach). First with several 3D printed parts that I designed and built myself. The Egg Finder sled in the nose cone, the electronics bay - which was a HUGE pain to get everything to fir properly, the charge wells, and the conformal rail guides were all designed specifically for this rocket by me, and printed by me. The two sleds were printed in PETg, and the rail guides and charge wells were printed with nylon. The rail guides were loosely based on the conformal ones that Wildman sells, you can download them here. If anyone is interested in the STL files for the other parts, let me know and I'll upload them to thingiverse and post links.
 

mpitfield

Moderator
Staff member
TRF Lifetime Supporter
Global Mod
Joined
Jul 7, 2013
Messages
4,904
Reaction score
432
Location
Toronto, Ontario
If nothing else, I learned a hell of a lot with this rocket. It was my first MD build. Also my first using dual deploy. First using a GPS. First confirmed to break mach (Although I suspect I've had 2 other flights break mach). First with several 3D printed parts that I designed and built myself. The Egg Finder sled in the nose cone, the electronics bay - which was a HUGE pain to get everything to fir properly, the charge wells, and the conformal rail guides were all designed specifically for this rocket by me, and printed by me. The two sleds were printed in PETg, and the rail guides and charge wells were printed with nylon. The rail guides were loosely based on the conformal ones that Wildman sells, you can download them here. If anyone is interested in the STL files for the other parts, let me know and I'll upload them to thingiverse and post links.
Wow Chris you have really embraced some of the challenges of the hobby, good for you. I don't have a 3D printer however I am always interested in seeing what others do, and or invent, when it comes to this hobby. So feel free to post any pics or links to pics on what your setup was, as well as the parts you designed.

Good luck on the Punisher build and re-cert attempt. I have a 3" in my build pile, are you going with HED? If so I would love to see what you come up with for a setup...I see an L2 build thread in your future!
 

markkoelsch

Well-Known Member
Joined
Mar 18, 2009
Messages
4,364
Reaction score
149
Kevlar can be cut by fiberglass as others have noted. Chamfering the inside edge of the airframe is a good idea. Another is to put a couple wraps of duct tape around the cord at the location where the airframe and cord meet. The idea being that the tape will take some of the abuse, and is easily and cheaply replaced.

How long was the harness between the sections? I like to go long on harnessing.
 

Ccolvin968

Well-Known Member
Joined
Oct 11, 2016
Messages
314
Reaction score
0
Thanks Chris.
This will probably be my second project as well.
My Eggtimer classic went over with me just having to trim the ends a little shorter.
Otherwise it worked great.
I've been waffling about if I should get one or not, but you've pretty much sealed my fate.
Sounds like an awesome piece of equipment!
I definitely need one for my next project. :)
 

cerving

Owner, Eggtimer Rocketry
TRF Sponsor
TRF Supporter
Joined
Feb 3, 2012
Messages
4,366
Reaction score
1,742
Before the launch, my daughter asked what I'd do if we didn't get the rocket back (Which with the rocket and motor combination, I felt like that was a realistic possibility). I told her we'd go buy a new one, and try again. The first thing I did when we got back to the launch site was head over to Wildman West's tent, and bought a new kit (3" Punisher). We're now building that, and will hopefully launch it at RocStock next month.
You're a smart guy... get the daughter involved so Mom can't rag on you about it!

Hope Attempt #2 goes better... too bad I can't make the June ROCStock this year.
 

SoCalChris

Well-Known Member
Joined
Dec 9, 2015
Messages
91
Reaction score
0
Wow Chris you have really embraced some of the challenges of the hobby, good for you. I don't have a 3D printer however I am always interested in seeing what others do, and or invent, when it comes to this hobby. So feel free to post any pics or links to pics on what your setup was, as well as the parts you designed.

Good luck on the Punisher build and re-cert attempt. I have a 3" in my build pile, are you going with HED? If so I would love to see what you come up with for a setup...I see an L2 build thread in your future!
For the cert reattempt, I'm going to tone it down a bit. I plan on using a J270 and using the motor to deploy the chute, and I'll use my Jolly Logic chute release to bring it back down quickly.

However.... Once I've got that cert, I will be modifying it to use HED. I've got an L640 that I'd bought initially to get my L2 cert on before deciding to go with the j570 (I tend to go big or go home :D ). It is stable according to Open Rocket, so I'll hopefully be sending that up in a few months. I'm thinking drogue less deployment on that one.

Here's links to the items I 3d printed. I'll try to upload pictures of the Egg Finder sled later if anyone is interested.
Egg Finder and Battery Sled for Nosecone
38mm electronics sled
Charge well
Funnel for filling charge well with powder

View attachment 320189View attachment 320190

You're a smart guy... get the daughter involved so Mom can't rag on you about it!

Hope Attempt #2 goes better... too bad I can't make the June ROCStock this year.
Mom can rag all she wants about it, we're divorced and I don't need to listen to it any more :cheers:

Two of my daughters absolutely love rocketry though, so I'm more than happy to spend the time with them teaching how to build them, and why they work the way they do. My 10 year old has built a fiberglass kit by herself, and did a great job on it. We flew it on an I205 several months ago, and it flew superbly. She was incredibly proud of herself for building it, and she should be.

Her flight (Flown under my name since I'm certified, and she isn't)
[YOUTUBE]s08_FB1Y3_c[/YOUTUBE]
 

Latest posts

Top