Eagler's Nest

General Category => Off Topics and General Interest => Topic started by: CHARLES DEBOER on February 06, 2014, 06:42:58 PM

Title: Push rod elevator controls
Post by: CHARLES DEBOER on February 06, 2014, 06:42:58 PM

I decided to see if there was a weight penalty by going with the push rod elevator system. 

ELEVATOR PUSH ROD VS ORIGINAL DESIGN
WEIGHT IN ONCES
	PUSH ROD	ORIGINAL
PULLEY & FORWARD SLEEVE	0	3.4
PULLEY & REAR SLEEVE	0	1.6
FORWARD PUSH ROD & BEARING	9.5	0
REAR PUSH ROD & ROD ENDS	12.4	0
SLEEVE & BUSHING ON STICK	1.3	0
SLEEVE ON SLAVE ROD	1.6	0
BELLCRANK ASSY	3.2	0
TURNBUCKLES (2EA.)	0	0.9
CLEVIS FORKS & CLEVIS PINS (2 EA.)	0	2
22 ft. 3/32" CABLE	0	6
CABLE SLEVES & THIMBLES	0	0.7
STICK SLEVE	0	1
	28	15.6
DELTA	12.4

Title: Re: Push rod elevator controls
Post by: Sam Buchanan on February 06, 2014, 08:08:42 PM

Quote from: CHARLES DEBOER on February 06, 2014, 06:42:58 PM

I decided to see if there was a weight penalty by going with the push rod elevator system;

ELEVATOR PUSH ROD VS ORIGINAL DESIGN
WEIGHT IN ONCES
	PUSH ROD	ORIGINAL
PULLEY & FORWARD SLEEVE	0	3.4
PULLEY & REAR SLEEVE	0	1.6
FORWARD PUSH ROD & BEARING	9.5	0
REAR PUSH ROD & ROD ENDS	12.4	0
SLEEVE & BUSHING ON STICK	1.3	0
SLEEVE ON SLAVE ROD	1.6	0
BELLCRANK ASSY	3.2	0
TURNBUCKLES (2EA.)	0	0.9
CLEVIS FORKS & CLEVIS PINS (2 EA.)	0	2
22 ft. 3/32" CABLE	0	6
CABLE SLEVES & THIMBLES	0	0.7
STICK SLEVE	0	1
	28	15.6
DELTA	12.4

Two turnbuckles (and safety wire) only weigh 0.9 oz?

Don't forget to add the nearly double amount of material in the elevator horn for the cable system.

Title: Re: Push rod elevator controls
Post by: CHARLES DEBOER on February 07, 2014, 04:20:46 PM

Good catch Sam.  Turnbuckles should be 1.9 oz.  I couldn't figure out how you installed elevator stops so I went with XL's design.  That might knock off a couple more ozs,

Title: Re: Push rod elevator controls
Post by: Sam Buchanan on February 07, 2014, 05:02:44 PM

Quote from: CHARLES DEBOER on February 07, 2014, 04:20:46 PM

Good catch Sam.  Turnbuckles should be 1.9 oz.  I couldn't figure out how you installed elevator stops so I went with XL's design.  That might knock off a couple more ozs,

I forgot about the elevator stops, yep those things as built per plans are heavy. My stops are simply two adel clamps on the pushrod:

(https://www.eaglersnest.com/forum/proxy.php?request=http%3A%2F%2Fhome.hiwaay.net%2F%7Esbuc%2FlegaleagleXL%2Fcontrols-17.jpg&hash=dc70fcf1ed67c35779c641bddd934972820d0844)

This should put the cable system and pushrod system within mere ounces of each other. I had just made an estimate when evaluating the pushrod system, good to see you have put together numbers to show there is no significant weight penalty with pushrods. I've been asked this question before, now we have hard numbers.

The security, smoothness, and reliability of pushrods made it all well worth the effort for me.

Title: Re: Push rod elevator controls
Post by: rockiedog2 on February 07, 2014, 07:15:32 PM

that makes me feel better. on this new thing ive been picking at i cannibalized the elevator push pull system outa this derelict RV8 here and installed it grittin my teeth the whole time thinking i was adding a buncha weight. used the control stick and torque tube too. cut tons of steel outa that got the whole thing as light as possible. may be that i didnt add any weight much. also did a torque tube aileron setup cause of big interference with the fuel tanks if doing cables. that system would have required a buncha pulleys brackets offsets bellcranks and control arms all in double shear. the TT system is stone simple.
well thx for figuring all that up.