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.


Go Back   VAF Forums > Model Specific > RV-9/9A
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 01-11-2020, 10:34 AM
OneTwoTree OneTwoTree is offline
 
Join Date: Nov 2019
Location: DFW
Posts: 14
Default Real World Numbers, Am I Missing Something?

Let me start by saying long time lurker first time post. My mission is to travel and get my IFR ticket (for safety not for necessity). So naturally the 9 comes into picture. The 14 is a bit too rich for my blood. I want to be done at 80K with an IFR machine not 100K. The 9 is attractive, but I'm still dumbfounded that it only has a 36 gal capacity. Imagine my excitement when I find the Hotel Whiskey extended tanks. Then I ran the numbers:

empty weight 1050 (middle of average according to Van's site)
fuel weight 216 = 1266
A/C weight 48 = 1314 (Not negotiable according to the treasury)
HW ER Tanks 10 = 1324
ER fuel weight 60 = 1384
pilot weight 200 = 1584
co-pilot weight 150 = 1734

This leaves 16 pounds for bags ......... not good

When I run the same numbers for the 7 I get:

empty weight 1100 (middle of average according to Van's site)
fuel weight 252 = 1362
A/C weight 48 = 1410 (Not negotiable according to the treasury)
HW ER Tanks not needed
ER fuel weight not installed
pilot weight 200 = 1610
co-pilot weight 150 = 1760

40 pounds of bags.

You can't have it all. I know that. I could have the ER tanks installed and if they are unfilled I've added 60 pounds that I could carry (76 total for baggage).

Overall I'm just suprised that the 9 only has a 36 gallon capacity. I get that it's a cross counry maching for many reasons, but that is not one. Using 8GPH I'm getting 3.5 hrs aloft with a 1hr saftey buffer.
__________________
2020 Dues Paid
RV14-A Empennage Delevered 3/17/20
Reply With Quote
  #2  
Old 01-11-2020, 10:47 AM
climberrn's Avatar
climberrn climberrn is offline
 
Join Date: Oct 2008
Location: Carson City, NV
Posts: 639
Default

Your AC is basically 50Lbs ?baggage? that you carry with you at all times. As for endurance, 3.5 hours is about as long as I want to sit in the confines of my plane at one time. Even at that, with 1 fuel stop, I can be MORE than halfway across our country. I know the 7 has a little more fuel but realistically their numbers are not too far off with the smaller engine. 80k for an IFR machine is probably possible but unlikely in my opinion. That said, they are wonderful machines. As said many times before, build light.

Best of luck.
__________________
Joel

N626JA
RV-7A at CXP
Flying!
Reply With Quote
  #3  
Old 01-11-2020, 10:55 AM
Mike Hepperlen Mike Hepperlen is offline
 
Join Date: Oct 2010
Location: Crystal Lake, IL
Posts: 25
Default Fuel Capacity, Gross Wt. etc.

You might check out the RV-8, unless you have to have the side by side. It is much easier to enter and exit due to the canopy side rails and the roll over bar, and the 41 gallons fuel capacity will satisfy most everyone. It is a nice stable IFR platform and has 2 baggage bins. I installed an Lyc. 0-360 with hot tips and a Hartzell blended airfoil prop and got 183 knots @ 6000' with 75% power.

Mike Hepperlen
RV-4 & RV-8
Reply With Quote
  #4  
Old 01-11-2020, 11:16 AM
9GT's Avatar
9GT 9GT is offline
 
Join Date: Jan 2010
Location: Southern Michigan
Posts: 2,188
Default

I extended my RV-9A tanks 3.5 gallons each side for another hour of cruise flight just in case I ever need it. The modification didn?t add much weight since I just extended it a bay. The HW extended tanks add weight out into the wing tips, something I did not want.
__________________
David C.
Howell, MI
RV-10: #41686 Under Construction
RV-9A: #90949 Under Construction
RV-10: #40637 Completed/Sold 2016
Cozy MKIV:#656 Completed/Sold 2007
"Donor Exempt" but donated through Dec. 2021
Reply With Quote
  #5  
Old 01-11-2020, 01:56 PM
OneTwoTree OneTwoTree is offline
 
Join Date: Nov 2019
Location: DFW
Posts: 14
Default

Quote:
Originally Posted by 9GT View Post
I extended my RV-9A tanks 3.5 gallons each side for another hour of cruise flight just in case I ever need it. The modification didn?t add much weight since I just extended it a bay. The HW extended tanks add weight out into the wing tips, something I did not want.
I?ve been watching your updates on that. Your experience with the bad quality of quick build has me thinking of doing slow build wings and quick build fuselage.
Most of the trips I want to do regularly are 4 and 4.5 away in an RV. So 7 gallons would go a long way. Did you just swap the outer tank rib with another non tank rib to extend the tank or did you purchase other ribs through van?s?
__________________
2020 Dues Paid
RV14-A Empennage Delevered 3/17/20
Reply With Quote
  #6  
Old 01-11-2020, 02:11 PM
rocketman1988 rocketman1988 is offline
 
Join Date: Jun 2010
Location: Sunman, IN
Posts: 2,728
Default QB

I have no major complaints with the QB quality of my -10...
__________________
Bob
Aerospace Engineer '88

RV-10
N464RL

Dues+ Paid 2020,...Thanks DR+
Reply With Quote
  #7  
Old 01-11-2020, 02:17 PM
Kyle Boatright Kyle Boatright is online now
 
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 4,674
Default

Quote:
Originally Posted by rocketman1988 View Post
I have no major complaints with the QB quality of my -10...
I think most builders are PO'd when they find mistakes on QB kits. "I paid so I wouldn't have to fix stuff." But the reality is that if the guys in the factory do make mistakes despite all of the advantages they have (tooling, experience, oversight, etc), a guy building an airplane in his basement is likely to make even more (and probably worse) mistakes.

Obviously, there are exceptions.
__________________
Kyle Boatright
Marietta, GA
2001 RV-6 N46KB
2019(?) RV-10
Reply With Quote
  #8  
Old 01-11-2020, 02:23 PM
Northernliving Northernliving is offline
 
Join Date: May 2005
Location: Boston, MA
Posts: 591
Default

Quote:
Originally Posted by OneTwoTree View Post
I?ve been watching your updates on that. Your experience with the bad quality of quick build has me thinking of doing slow build wings and quick build fuselage.
Most of the trips I want to do regularly are 4 and 4.5 away in an RV. So 7 gallons would go a long way. Did you just swap the outer tank rib with another non tank rib to extend the tank or did you purchase other ribs through van?s?
Have you checked out the Pat Tuckey tanks? That's my plan. Mike Stewart also did something similar http://mstewart.net/super8/ertanks/Index.htm

I agree that 3.5-4 hours is usually enough time. However, there are times where I would really like 1-2 more hours to avoid a stop.
__________________
Brian J.
Boston, MA
RV8 Based at ORH - Purchased
RV8 - The Project #83313 - Under Construction
Reply With Quote
  #9  
Old 01-11-2020, 02:25 PM
Dan B Dan B is offline
 
Join Date: Mar 2006
Location: Edmond, OK
Posts: 217
Default RV9 36 Gal Fuel Capacity

We have the IO-320 engine with GAMI injectors and run it lean of peak during cruise. 36.0 gallon fuel capacity.

Our RV-9 engine data down load for a trip climbing to 10,000 cruise altitude from our home airport at 1100' elevation is as follows:

Time and fuel burn beginning at engine start, including taxi, climb, and cruise (148kts TAS), for the first hour the fuel burn was 6.0 gal. There after, fuel burn was 6.3 gph at 148kts TAS. An additional 3.0 hours of cruise will still leave you with 10 gallons of reserve fuel.

The TAS on our RV9 will increase to about 153kts, burning 6.7 gph at 9000'-12000'.

That amount of fuel endurance will give most bladders a challenge.
__________________
Dan Burdette
RV-9A, IO-320
Skyview, Garmin GTN750xi, TT Gemini AP
CFI, CFII, ATP
Guthrie-Edmond Rgnl, OK (KGOK)
________
Reply With Quote
  #10  
Old 01-11-2020, 02:27 PM
rmartingt's Avatar
rmartingt rmartingt is offline
 
Join Date: Nov 2006
Location: Savannah, GA
Posts: 1,133
Default

A couple of things to consider... A/C is heavy and takes a lot of power for something you're only using at low altitude. I've traveled with Dad in his RV-6 in the middle of summer and he lives near Atlanta; travel seems best accomplished by leaving as early in the morning as you feel comfortable doing, and climbing to altitude where it's much cooler. When you need to stop for gas, come down, get it over with, and climb back to cool air. There might be a bit of discomfort that way, till you get to altitude but the air vents deliver plenty of air. I know coming back from Oshkosh I got cold and wished for a sweatshirt. Mom and Dad make lots of trips in that airplane all year with no AC. The high UV-tint canopy and a good sunshade or two will help as well.

Besides, you probably don't want to fly in the hottest part of the day anyway--it's bumpy and a popular time for thunderstorms.

The -9 should theoretically climb a little faster than a -7, cruise a little higher, and/or burn a bit less fuel for the same speed. Theoretically. Consider what a realistic fuel burn number might be compared to your fuel load. Things like balanced fuel injection (mechanical or electronic) and electronic ignition can give you better efficiency, as can good drag-reduction work.

Ask yourself how much you really need/want the extra gas for--after all, your bladder is only so big, and a lot of people really want to get out and stretch after a while. Are you just looking for IFR reserves? Planning to make looooong nonstop flights? Or are you just looking to "tanker" fuel? (the last is the main reason why I added capacity--I plan to run mogas most of the time and wanted to be able to fly out and back within the southeast, without refueling).

Other options for more gas are closing out your wingtips (on a short-wing you get about 9gal/side, not sure what it'll get you on a -9 but it's a bit less IIRC) or making another tank out of your outboard leading edge (AKA the "Tuckey tanks" mentioned; it got me about 13/side on my -7 and I could have gone higher). There are pros and cons to both approaches; both are probably lighter than the HW tanks but are more work to install. I'll just leave the grenade about relieving bending moments, gross weight increases, etc. right here and walk out
__________________
RV-7ER - canopy and wiring
There are two kinds of fool in the world. The first says "this is old, and therefore good"; the second says "this is new, and therefore better".
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 06:43 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.