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Hot Hopper (finished!)
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Hot Hopper (finished!)
I was pondering how to build a fairing/ nacelle around a bee tank or a horse shoe backplate. I realized that a Space Hopper is basically a TD case. So I modded out a Hopper to compete in the fall speed event. It sports a KB crank, #4 P/C, Nelson head and a KK NVA. I also did a little massaging of my own.
I bagged all the original parts to re-install upon retirement.
I bagged all the original parts to re-install upon retirement.
Last edited by Cribbs74 on Tue May 27, 2014 9:40 pm; edited 2 times in total
Cribbs74- Moderator
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Posts : 11892
Join date : 2011-10-24
Age : 50
Location : Tuttle, OK
Re: Hot Hopper (finished!)
Cool! Have you run it yet? It would be interesting to see what it tachs on 25% and 5/3 prop.
crankbndr- Top Poster
- Posts : 3058
Join date : 2011-12-10
Location : Homestead FL
Re: Hot Hopper (finished!)
I'll let you know. I am messing with it now. I'll also try and do video.
Cribbs74- Moderator
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Posts : 11892
Join date : 2011-10-24
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Re: Hot Hopper (finished!)
Uh oh!Cribbs74 wrote:
_________________
Don't Panic!
...and never Ever think about how good you are at something...
while you're doing it!
My Hot Rock & Blues Playlist
...and never Ever think about how good you are at something...
while you're doing it!
My Hot Rock & Blues Playlist
RknRusty- Rest In Peace
- Posts : 10869
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Age : 68
Location : South Carolina, USA
Re: Hot Hopper (finished!)
Here is a preliminary video. I wasn't happy with it. This is the 4th KB crank I have messed with and yet again it vibrated like crazy. I am about to give up on those things permanently. Does anyone else have a problem with them?
Here is a video of the run, I have since switched to a Bee crank and the vibes are gone....go figure. That's also why I don't use them in my tach race engines. It sounded too slow to even bother with a tach. I'll take a video of the Bee cranked version for comparison.
Take note of the explosive finish. I didn't want to bother building a new bladder.
Here is a video of the run, I have since switched to a Bee crank and the vibes are gone....go figure. That's also why I don't use them in my tach race engines. It sounded too slow to even bother with a tach. I'll take a video of the Bee cranked version for comparison.
Take note of the explosive finish. I didn't want to bother building a new bladder.
Cribbs74- Moderator
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Posts : 11892
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Re: Hot Hopper (finished!)
Ron,
I've had five KB cranks. The first two were garbage, vibrated the case oblong in short order. The last three purchased in the last 18 months or so have been great. I have one in my flight time contest engine, over three hours at 21k+ and running smooth. That's the engine that was in my winning speed plane. The corsair also has a kb crank.
For some reason I get better rpms with #1 cylinders on my reedies. It may just be the fit of my particular cylinders.
Jim
I've had five KB cranks. The first two were garbage, vibrated the case oblong in short order. The last three purchased in the last 18 months or so have been great. I have one in my flight time contest engine, over three hours at 21k+ and running smooth. That's the engine that was in my winning speed plane. The corsair also has a kb crank.
For some reason I get better rpms with #1 cylinders on my reedies. It may just be the fit of my particular cylinders.
Jim
JPvelo- Diamond Member
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Join date : 2011-12-02
Age : 56
Location : Colorado
Re: Hot Hopper (finished!)
Audio tach had you steady at 17,198 rpm
1/2A Nut- Top Poster
- Posts : 3402
Join date : 2013-10-20
Age : 60
Location : Brad in Texas
Re: Hot Hopper (finished!)
Hey Nut, what are you using for an audio tach, is it freeware?1/2A Nut wrote:Audio tach had you steady at 17,198 rpm
Rusty
_________________
Don't Panic!
...and never Ever think about how good you are at something...
while you're doing it!
My Hot Rock & Blues Playlist
...and never Ever think about how good you are at something...
while you're doing it!
My Hot Rock & Blues Playlist
RknRusty- Rest In Peace
- Posts : 10869
Join date : 2011-08-10
Age : 68
Location : South Carolina, USA
Re: Hot Hopper (finished!)
1/2A Nut wrote:Audio tach had you steady at 17,198 rpm
Neat. Thanks Nut, yeah like I said It sounded slooooow! Audio tach agrees
Cribbs74- Moderator
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Posts : 11892
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Re: Hot Hopper (finished!)
Yes smart phone app called (RPM Gauge) has an add free version for a few bucks.
1/2A Nut- Top Poster
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Re: Hot Hopper (finished!)
Must be an Android thing as I can't find an Iphone version.
I was interested even though I have a regular tach. I do all my testing in the shop and I can't use my normal tach inside due to fluorescent lighting. So that means I have to turn off the lights and rig another light source. It's kind of a pain.
Ron
I was interested even though I have a regular tach. I do all my testing in the shop and I can't use my normal tach inside due to fluorescent lighting. So that means I have to turn off the lights and rig another light source. It's kind of a pain.
Ron
Cribbs74- Moderator
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Posts : 11892
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Re: Hot Hopper (finished!)
Ron,
Here's a little inspiration for you:
http://www.ebay.com/itm/1960-SPEED-PLANE-with-Space-Hopper-Model-Airplane-Engine-/161314369568?pt=Radio_Control_Parts_Accessories&hash=item258f15f020
Here's a little inspiration for you:
http://www.ebay.com/itm/1960-SPEED-PLANE-with-Space-Hopper-Model-Airplane-Engine-/161314369568?pt=Radio_Control_Parts_Accessories&hash=item258f15f020
JPvelo- Diamond Member
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Join date : 2011-12-02
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Re: Hot Hopper (finished!)
Very nice Jim!
I like it. Although I would probably TD that bad boy.
Here is a video from this afternoon. I am getting there, but still not happy yet.
I like it. Although I would probably TD that bad boy.
Here is a video from this afternoon. I am getting there, but still not happy yet.
Cribbs74- Moderator
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Posts : 11892
Join date : 2011-10-24
Age : 50
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Re: Hot Hopper (finished!)
I have a 1/2a speed pan I need to do something with. How about the pitch in that prop!Cribbs74 wrote:Very nice Jim!
I like it. Although I would probably TD that bad boy.
Jim
JPvelo- Diamond Member
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Re: Hot Hopper (finished!)
Yeah, looks like a 7 or 8 pitch. RPM must have suffered under that load. Buy it Jim!
Cribbs74- Moderator
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Re: Hot Hopper (finished!)
Nah, I have the pan and plans to make my own.Cribbs74 wrote:Yeah, looks like a 7 or 8 pitch. RPM must have suffered under that load. Buy it Jim!
JPvelo- Diamond Member
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Re: Hot Hopper (finished!)
Yeah.... But it has a space hopper in it.
I am beginning to wonder if the intake diameter is limiting me. I am not going to drill it and find out.
I am beginning to wonder if the intake diameter is limiting me. I am not going to drill it and find out.
Cribbs74- Moderator
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Re: Hot Hopper (finished!)
Did you remove the screen?Cribbs74 wrote:Yeah.... But it has a space hopper in it.
I am beginning to wonder if the intake diameter is limiting me. I am not going to drill it and find out.
JPvelo- Diamond Member
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Re: Hot Hopper (finished!)
No I did not. I am not wanting to do anything irreversible. I'll take a peek and see if it can be done.
Another option would be to close up the intake on a TD and see how it does with the SH backplate.
Another option would be to close up the intake on a TD and see how it does with the SH backplate.
Cribbs74- Moderator
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Re: Hot Hopper (finished!)
Cribbs74 wrote:
Another option would be to close up the intake on a TD and see how it does with the SH backplate.
Ron,
To eligible for Reed Speed it needs to be reed valve case, no modded TDs'.
Jim
JPvelo- Diamond Member
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Re: Hot Hopper (finished!)
Thanks......
Guess I will keep trying.
Guess I will keep trying.
Cribbs74- Moderator
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1/2A Nut- Top Poster
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Re: Hot Hopper (finished!)
Well, it's an improvement in the right direction anyway......
Thanks Nut.
Thanks Nut.
Cribbs74- Moderator
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Re: Hot Hopper (finished!)
Ok,
I am satisfied with it now. I got it to turn over 19K on a Cox 5x3.
With the APC 4.75x4 I should be in the 20K range and competitive. I didn't have one on hand to try.
Here is a video of the results. I apologize for the bad camera work I kept setting the phone down to work the needle. I also had to keep moving the tach around to catch the light for the tach to read right...
All I did is use a nut without the screen and remove a head shim.
I am satisfied with it now. I got it to turn over 19K on a Cox 5x3.
With the APC 4.75x4 I should be in the 20K range and competitive. I didn't have one on hand to try.
Here is a video of the results. I apologize for the bad camera work I kept setting the phone down to work the needle. I also had to keep moving the tach around to catch the light for the tach to read right...
All I did is use a nut without the screen and remove a head shim.
Cribbs74- Moderator
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Posts : 11892
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Re: Hot Hopper (finished!)
Nice! What % nitro?
JPvelo- Diamond Member
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