Cox Engines Forum
You are not logged in! Please login or register! Guests are limited to posting in the "General Questions (Guest Posting Allowed)" section only. Becoming a member is fast, easy and FREE!


Log in

I forgot my password

Search
 
 

Display results as :
 


Rechercher Advanced Search

Cox Engine of The Month
February-2018
coxaddict's

"Another Twin Born 2-2-2018 weight 4 oz."



PAST WINNERS
Speed Contest 2018
CEF Traveling Engine

Win This Engine!
The Traveling Prop
Gallery


World of Aviation

My money is on the table too.

Page 2 of 2 Previous  1, 2

Go down

Re: My money is on the table too.

Post  Oldenginerod on Sun Oct 23, 2016 3:55 pm

Davenz13 wrote:

I'm worried about what the Castor oil & prop-wash is gonna do for her complexion lol!
avatar
Oldenginerod
Diamond Member
Diamond Member

Posts : 1986
Join date : 2012-06-15
Age : 55
Location : Victoria, Australia

View user profile

Back to top Go down

Re: My money is on the table too.

Post  Davenz13 on Sun Oct 23, 2016 4:33 pm

Thanks Rusty. Coming from a master builder like yourself I’ll take that as a huge compliment.

I’ve had a worrying doubt about the height of the tether bracket too so with a consensus of two votes   Hand Shake  and a plastic hammer a quick modification was made and it now has 24mm clearance.
The good thing about plan A is plan B is only one step away.



Using a bar the point of balance is 13mm back (towards the rear of the car) from the hole in the bracket. Hanging the car on a string from the hole the car hangs slightly rear down.
Too much rear bias and I imagine the car will try to broadside its way around and end up rolling.

I can easily make and fix a T shape bracket to the tether bracket with the top of the T facing fore and aft with a line of holes along it. That’ll give me a series of fixing options to play with.
I’d like to start from a completely neutral bias and go from there. There’s still more weight to add to it too, props, spinners and rear narcelles not to mention a couple of coats of fuel proof clear.

I guess I won’t know what’s going to happen as the centrifugal force increases until it happens.  affraid

When you guys fly twins don’t you fuel it so the outboard engine quits first. I thought it might be a good idea to have the first run on the inboard engine only. Huh...

I like the idea of a temporary roll cage so that with have to enter the mix as well. The axles will provide good fixing points as the don’t turn and are easy to get at.
avatar
Davenz13
Gold Member
Gold Member

Posts : 259
Join date : 2013-11-28
Age : 62
Location : Palmerston North, New Zealand

View user profile

Back to top Go down

Re: My money is on the table too.

Post  Oldenginerod on Mon Oct 24, 2016 2:19 am

Davenz13 wrote:
I like the idea of a temporary roll cage so that with have to enter the mix as well. The axles will provide good fixing points as the don’t turn and are easy to get at.

Apart from the chance of breaking a prop in the case of a rollover, the only real danger is to the cosmetics.  Maybe just tape it over with bubble-wrap for finish protection. Huh...
avatar
Oldenginerod
Diamond Member
Diamond Member

Posts : 1986
Join date : 2012-06-15
Age : 55
Location : Victoria, Australia

View user profile

Back to top Go down

Re: My money is on the table too.

Post  KariFS on Mon Oct 24, 2016 2:37 am

And be sure your pilot wears a hair net or at least a ponytail to avoid her hair getting tangled in the propellers affraid
avatar
KariFS
Platinum Member
Platinum Member

Posts : 1184
Join date : 2014-10-10
Age : 46
Location : Finland

View user profile

Back to top Go down

Re: My money is on the table too.

Post  Davenz13 on Mon Oct 24, 2016 3:31 am

She does have a full face helmet but getting all that hair in there might be an issue so I  think the first few runs might be in the style of the headless horseman or in this case

the headless pitstop lol!
avatar
Davenz13
Gold Member
Gold Member

Posts : 259
Join date : 2013-11-28
Age : 62
Location : Palmerston North, New Zealand

View user profile

Back to top Go down

Re: My money is on the table too.

Post  Davenz13 on Tue Nov 01, 2016 10:10 pm

Well the car has been stripped and the body has gone off to have fuel-proof clear coat applied.

The engine mount has been detailed and engines fitted just to make sure everything fits. I've never been a big fan of self-tapping screws in plastic (tendency to split) and fine threads have a tendency to strip so I put the narcelles in the lathe and carefully turned a groove through the screw mounts, drilled out the holes and fitted nuts to the mounting screws.  



Next phase is making a test bed and running the engines. Slowly getting there.
avatar
Davenz13
Gold Member
Gold Member

Posts : 259
Join date : 2013-11-28
Age : 62
Location : Palmerston North, New Zealand

View user profile

Back to top Go down

Re: My money is on the table too.

Post  Davenz13 on Tue Jun 20, 2017 2:46 am

Well, you know how you’re trying to get something done and life just keeps getting in the way. That’s what seemed to keep happening every time I tried to get back on this little project. This “build a tether car” idea was put forward by Mark (batjac) in September 2015. My, how time flys.  But while dealing with life I’ve been chipping away at it in the background and making some slow progress. I still managed to have a quick peek at the forum every now and then to see what everyone else was up to.
At the last update there were two things to check before an actual run.

1. Test the cars exterior coating against the fuel
2. Run the motors.

The exterior coating versus fuel test
This was done scientifically (I poured fuel all over a similar item and watched result) in a controlled environment (my workshop). Even after several weeks there was no indication of any effect to the exterior coating whatsoever. I’ve reached the conclusion that these car bodies are immune to the effects of the fuel. The first test run will prove this theory either right or wrong.  
I also located two more tin bodies, one of which I’ll use for the initial runs. Don’t have to worry so much now about damaging the car if I have a mishap or my theory about the fuel turns out to be wrong during testing. Never hurts to have a few spares.
The spare bodies have been drilled and all ready for use by just transferring the running gear and engines over.  Red number 09 has been nominated as the initial test car. Seemed fitting since the driver is a mechanic.
 


Running the motors
I needed a test bed to run the engines on and also to see what changes make them run better or worse.
I’ve seen some good ideas and examples of test rigs on the forum here but building one from scratch would just take me too long (it’s taken me nearly two years to get the car this far). I’d seen a Turnigy thrust stand on special from HobbyKing a while back and I thought it was a neat little item so purchased it and put it in the cupboard as one of those “come in handy one day” purchases. Receipt says December 2014, (Wow didn’t realise that much time had passed)
It’s for electric motors but I’m thinking it won’t take much to convert it from testing electric motors to fuel.  



I decided it might be better to have this as a separate post so I'll detail it under "Turnigy thrust stand conversion"  



Last edited by Davenz13 on Sun Oct 22, 2017 7:38 pm; edited 1 time in total
avatar
Davenz13
Gold Member
Gold Member

Posts : 259
Join date : 2013-11-28
Age : 62
Location : Palmerston North, New Zealand

View user profile

Back to top Go down

Re: My money is on the table too.

Post  Oldenginerod on Tue Jun 20, 2017 6:26 am

Well done Dave. Good to see you making some progress.
avatar
Oldenginerod
Diamond Member
Diamond Member

Posts : 1986
Join date : 2012-06-15
Age : 55
Location : Victoria, Australia

View user profile

Back to top Go down

Re: My money is on the table too.

Post  Sponsored content


Sponsored content


Back to top Go down

Page 2 of 2 Previous  1, 2

Back to top

- Similar topics

 
Permissions in this forum:
You cannot reply to topics in this forum