VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.

  #1  
Old 01-28-2016, 05:26 AM
StuBob StuBob is offline
 
Join Date: Oct 2015
Location: Indianapolis, IN
Posts: 254
Default Build Light; Go Fast

Perusing this site while the primer dries, I find many admonishments to "build light." Was it Art Chard who said to "add lightness?" Sounds good to me. But where does this lightness come from? Since I'm just getting started, I have plenty of opportunity to add it everywhere from the rudder forward.

A related but separate issue is speed. I have a Bonanza. I REALLY want my RV to be a Bonanza killer. But some things remove lightness while adding speed.

So......

1)What are some concrete examples of how you've "built light" or seen it done? I can think of a handful: Minimize priming. Minimize interior/soundproofing. Maybe minimize avionics, but they don't weigh what they used to. I suspect a G3X weighs less than steam gauges with a vacuum pump and plumbing. Light prop (composite or wood). Parallel-valve engine. Polish, don't paint. Lightweight battery.

2)What are some concrete examples of how you've gotten a fast airplane, or known of others to get one? Maybe: More horsepower -- angle-valve 360, Rocket, etc. Constant speed prop. Build light!

But angle valve motors and constant speed props add more weight than you'll ever save by minimizing the interior.

So, tell me your experience with building light and flying fast!
__________________
Stu F.
RV8
Reply With Quote
  #2  
Old 01-28-2016, 06:45 AM
MikeyDale's Avatar
MikeyDale MikeyDale is offline
 
Join Date: Aug 2012
Location: Garden City Texas
Posts: 890
Default

I think my biggest mistake in this area was painting! The bottom of the wings, HS, and control surfaces should have had the very minimal paint. Just enough for corrosion protection. Full color saturation is not needed. No one ever looks at the bottom of the plane except me!
__________________
Mike Hillger
RV 7 FLYING SINCE 4/2015!
Garden City, Texas
First Flight https://www.youtube.com/watch?v=QqgxhWH3pqA
Dues Paid
Reply With Quote
  #3  
Old 01-28-2016, 07:36 AM
judoka5051 judoka5051 is offline
 
Join Date: Aug 2010
Location: McAlpin, FL
Posts: 257
Default Did it!

Hey Stuart,

Search my posts. I spent a lot of time thinking about how to keep it light and fast. I posted most of my ideas in one spot. I ended up with a 975 lb RV8A that cruised 205mph at 10,500 on 160hp.

Lance
__________________
Lance Logan
McAlpin, FL
Plane at FL10

Scratchbuilt Biplane
Preceptor N3 - Sold
Zenith Zodiac 601HD - Sold (good riddance)
Kitfox IV - Sold my share, but loved that plane
RV8A Sold! Loved the plane, but not the nosewheel!
RVX (RV6/4) Sold
Cherokee 180 pickup truck
RV8 Fastback
Reply With Quote
  #4  
Old 01-28-2016, 07:44 AM
cderk's Avatar
cderk cderk is offline
 
Join Date: Sep 2015
Location: Park Ridge, NJ
Posts: 693
Default

Before you get all crazy - I would really love to see what the difference is in speed between a "fully loaded" RV, versus one, as you call it is "kept light".

If you're only getting a few knots faster by keeping it light, is it really worth it? Even 5 knots faster... does it really matter? I'd rather have all the "creature comforts" and be 5 knots slower
__________________
RV10
First Flight Apr 6, 2020
Reply With Quote
  #5  
Old 01-28-2016, 07:59 AM
Toobuilder's Avatar
Toobuilder Toobuilder is offline
 
Join Date: Jul 2009
Location: Mojave
Posts: 4,736
Default

Building light is a mindset more than a technique. Yes, your examples are valid, but building light should be on your mind with every decision you make. Build the airplane for the mission, but make it as light as you can to meet that requirement. It makes no sense to minimize avionics if you intend to fly hard core IMC; on the other hand, don't do like the builder of my Rocket and run 14 AWG wire out to power the nav lights. Minimize flex hose wherever possible, and when needed, run the shortest hose you can. Sure that little sender manifold Vans provides is convenient, but does it make sense to run 5+ feet of firesleved hose back and forth across the firewall when a 6 inch hose, an adel clamp and a little extra wire would serve the exact same purpose? Similarily, do you really need a length of firesleved hose to feed the MP guage? No. Not at all. How about 3 axis trim? Slightly nice to have but is it worth the added weight? I didn't think so on my Rocket and now I'm building a new aileron and rudder after removing the servo's, tabs and wiring.

Power adders like going with an angle valve engine will improve the power to weight ratio of an identical airplane, but go overboard and a lighter, lower powered example will match or beat yours. Added power is a tough way to build all out speed with RV's because they really start hitting the wall. More power generally gives you better climb, but not a whole lot of speed. If you want speed, then pay attention to fairing alignment, rigging, and probably most important, cooling drag.

But now is the time to be thinking about light and speed - it's very tough to change things once the airplane is flying.
__________________
WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.

Michael Robinson
______________
Harmon Rocket II -SDS EFI
RV-8 - SDS CPI
1940 Taylorcraft BL-65
1984 L39C

Last edited by Toobuilder : 01-28-2016 at 08:06 AM.
Reply With Quote
  #6  
Old 01-28-2016, 08:08 AM
brad walton brad walton is offline
 
Join Date: Jul 2007
Location: Cypress, TX
Posts: 527
Default

"Build light" philosophy also has more to do with handling and feel of the aircraft in flight. How it flys rather how much faster. The joy of an RV is its nimbleness.
Reply With Quote
  #7  
Old 01-28-2016, 10:02 AM
RVbySDI's Avatar
RVbySDI RVbySDI is offline
 
Join Date: May 2005
Location: Tuttle, Oklahoma
Posts: 2,571
Default

Quote:
Originally Posted by Toobuilder View Post
Building light is a mindset more than a technique. Yes, your examples are valid, but building light should be on your mind with every decision you make. Build the airplane for the mission, but make it as light as you can to meet that requirement. It makes no sense to minimize avionics if you intend to fly hard core IMC; on the other hand, don't do like the builder of my Rocket and run 14 AWG wire out to power the nav lights. Minimize flex hose wherever possible, and when needed, run the shortest hose you can. Sure that little sender manifold Vans provides is convenient, but does it make sense to run 5+ feet of firesleved hose back and forth across the firewall when a 6 inch hose, an adel clamp and a little extra wire would serve the exact same purpose? Similarily, do you really need a length of firesleved hose to feed the MP guage? No. Not at all. How about 3 axis trim? Slightly nice to have but is it worth the added weight? I didn't think so on my Rocket and now I'm building a new aileron and rudder after removing the servo's, tabs and wiring.

Power adders like going with an angle valve engine will improve the power to weight ratio of an identical airplane, but go overboard and a lighter, lower powered example will match or beat yours. Added power is a tough way to build all out speed with RV's because they really start hitting the wall. More power generally gives you better climb, but not a whole lot of speed. If you want speed, then pay attention to fairing alignment, rigging, and probably most important, cooling drag.

But now is the time to be thinking about light and speed - it's very tough to change things once the airplane is flying.
This is as true as it gets! If it is your goal then EVERYTHING you build, assemble, install should be examined to determine what is absolutely necessary and what can go. Decisions on every system will affect the weight.

Here are just a few examples that I dealt with when trying to keep it light. Some were realized in the construction of components, some were decisions on what systems to install and how they would be installed:

Decisions:
  1. Install a 180 HP IO-340 instead of 180 HP IO-360
  2. Install Catto fixed pitch prop instead of constant speed prop
  3. Install all electronic glass panel with no round gauges
  4. Did not install passenger side brake pedals
  5. Installed standard Van's baffle kit instead of plenum
  6. Used Van's supplied plastic brake lines instead of stainless steel lines I had originally planned installing
  7. Install wiring for lights in wings, tail, etc. without conduit. Wires are just run through ribs and bulkheads using snap bushings and secured with lace.
  8. Install new LiPo4 battery (recent decision that saved 12 lbs)

Construction:
  1. Any bracket or flat plate surface that had area to do so, I drilled out lightening holes. Saved only ounces on any given individual component but as a whole saved a lb or two overall. Examples of this include the plates used to mount EFIS magnetometers. I weighed these plates before and after the lightening holes during construction. each of the two plates lost 2 ounces after drilling out the lightening holes.
  2. used lace to tie electrical wiring instead of zip ties. Again minuscule individual savings but does add up with everything else. Plus there is the added benefit of not dealing with those sharp edges that slice your hand open if you are careless with trimming the zip ties.

Most likely other items I am forgetting at the moment but everything adds up if you are serious about weight savings. It really is a mind set more than anything else.
__________________
RVBYSDI
Steve
RV9A
https://rvwings.com

Live Long And Prosper! 🖖🏻
Reply With Quote
  #8  
Old 01-28-2016, 10:12 AM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
Posts: 4,645
Default

It saves about a pound and it's so easy....

Replace the AN365 nuts with MS21042.

And less than a pound and not as easy, round every corner.

Dave
Reply With Quote
  #9  
Old 01-28-2016, 11:39 AM
diamond diamond is offline
 
Join Date: Sep 2009
Location: Rochester, MN
Posts: 710
Default

A pound here, a pound there. I think before I go crazy with all the little variations, I'll get naked in front of the mirror and ask myself if I can trim a few pounds here and there.
Reply With Quote
  #10  
Old 01-28-2016, 12:00 PM
CATPart CATPart is offline
 
Join Date: Jan 2012
Location: up up and away
Posts: 312
Default

here are some engine related notes I copied from here and elsewhere on the net. sorry but I don't know who wrote this.

"Here are some thoughts on using the 0-320 in the Panther. The E2D dyna focal is listed at 268 lbs. This weight is from days gone by before light wt. starters and alternators, taper fin cylinders, and magnesium sumps all of which can be installed to bring the weight down from 268 to the 240-245lb range. The sky tec starter is @ 6 1/4 lbs. I'm not sure about the B&C 8.5 amp alternator but I think it weighs about 1/2 of a 20-40 amp up on the front. The starter ring gear can be modified by shaving off the V belt drive pulley and drilling lightning holes in it. I just did one and it went from 6 3/8 to 5 lbs, or Sky dynamics has a magnesium one that weighs less. Changing out mags to P-mags and using auto plugs instead of standard ($30) aviation plugs will reduce another 6-7lbs. The magnesium sump is 7 lbs lighter than the standard sump.

On my last project I built a set of intake tubes out of aluminum and saved 2 1/4 lbs. If I remember correctly the taper fin cylinders are 2 lbs each lighter so save another 8 lbs. there. One more area is the oil screen vs. the oil filter adapter and oil filter. I would elect to use the standard oil screen and housing which is @ 1-1/5 lbs.

Another big area is using carbon fiber plenums instead of standard engine baffling. Take off at least 5-6 lbs and the plenums do a great job at cooling.
The bottom line is simple. The 0-320 can be made a lot lighter than original--it just boils down to how much money you are willing to spend to get rid of each pound of weight. Any of the above mods mentioned do not take away from the safety or longevity of the 0-320. I hope this info helps when you need to decide on your Panther engine. Larry Vetterman.

Narrow Deck 0320 fitted with tapered intake tube sump. I am told this sump and engine combination can save about 18 lbs over a wide deck regular sump. You should verify this. Bart at Aerosport Power in Kamloops BC stockpiles these kinds of parts for Super Cub enthusiasts.
If you want a really light weight sump, see if Cubcrafters will sell you theirs. It is reported to save 10 pounds over the normal cast sump. Not sure what it saves over the tapered intake tube sump.

A B&C alternator driven off of the accessory drive will save you some weight and no need for a drive belt. The output is limited, but no problem if you dont have a lot of avionics. I have one on my Bucker."
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 10:35 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.