RV-10 actual W&B scenario (Anyone been there, done that?)

Hi All-

This is a word problem for anyone with an RV-10 similar to N402RH, Rob Hickman's from Advanced Flight Systems. (Rob, if you read this, you can answer too.) RV-10 with good paint & interior and AFS glass panel, servos, ADAHRS, etc. but not built-in O2 (I have portable for those few times...) and the 2800 lb Gross Weight:

I'm pounding away on the tailcone, still worrying about future W&B and performance etc., and got the epiphany to just ask those who have gone before, if the RV-10 will actually make my mission. (Yep, should have done this before rivet #1.)

I want to put the following weights in the cabin (no big & tall jokes, please), add maybe 100 pounds of weekend junk, and fly not more than two hours with a 45-60 minute IFR reserve at the magic 170 kts, using the typical IO-540DA45. If prop makes a difference, tell me.

Pilot (me): 220, in clothes, my winter weight.
Front pax: 190, wonderful mom, great cook!
Rear right: weighing in at 320, our friend Bob (not his real name), 6'5" of former college football linebacker and world-class deer hunter.
Rear left: his demure sweetheart of a paltry 140 lbs, fully clothed, with handbag.

Given 3 hours of total fuel (11 gph?), CAN IT BE DONE? If not, how much gas after those people? How much left over for baggage junk? CG issues?

Please tell me your real-life stories: W&B, speed, fuel load, reserve, bags, etc. If you have actual numbers, graphs, charts, calaculators, pictures, video or hairy/scary war stories, please tell me. If impossible, say so. This is my worst-case mission, and not just me & the Mrs and two middle-schoolers going to OSH with a tent and a camp stove which should also happen.

Thanks,
-Scott
Columbia, SC

I have a pretty light -10 at 1602 lbs bew. Also pretty forward empty cg.
I don't want to be looking outside to see if the wings are still on every time I hit turbulence, so I use 2700 lbs for gross. That said, I can carry:
Your pilot/passenger load, but the linebacker has to sit up front (cg issue).
That leaves me 30 gal of gas, good for 3 hours to empty at 10 gal/hr LOP and 160 KTAS (not 170 as you asked for) and 50 lbs of baggage (not the 100 lbs you asked for).
If you are willing to fly at 2750 lbs, then my -10 could carry all 100 lbs of bags - but about 30 lbs of those bags have to go forward, at the passengers' feet, or between the front seats. (cg issue). If willing to fly at 2800 lbs, you could add another 8 gal of gas - 3.8 hrs endurance at 160 KTAS, or 2.9 hrs at 170 KTAS.
So yes, it can be done. Build it light.

Not quite

Scott,
While the -10 is a very capable aircraft for moving people and belongings, I'm afraid it isn't as capable as you're hoping.

My -10 has everything you asked for and comes in at 1707 lbs empty weight with a ramp weight of 2707. I believe the -10 has a max gross of 2700, not 2800.

If I load you, your wife, and your buddy and include 40 gallons total, I'm coming in at 2677. That means that you can throw in another 30 lbs before max weight but you're leaving your friends wife behind and 70 lbs of your personal stuff.


If I calculate all passengers and no baggage at all, I can squeeze roughly 10 gallons into each tank

Does this help?

David

Van's recommends 2700 as the GW but you as the builder are free to set it at whatever you want (I set my at the recommended 2700).

So I ran your numbers for my plane and it works if you have one tank of gas (30gal) which will leave you a bit shy of your endurance goal. At takeoff you are close to aft CG and if you get down to 5 gals you are one the line and any less you'll exceed aft CG.

If you put the wives in back as Bob suggested, the aft CG issue goes away.

If you set your GW higher than Van's recommendation you gain fuel and endurance but the potential CG issue remains the same.

IMO setting the GW higher is not the way to go, others will disagree. I echo Bob's advice to build as light as you can and figure out other ways to reduce passenger weight. YMMV....

I would be seriously concerned having a 320 lb person on the step, and the wing walk area.

Bill.Peyton said:

I would be seriously concerned having a 320 lb person on the step, and the wing walk area.

Click to expand...

A 340lb person used to frequently use the step of a 6a and the wing walk area of 3 different SBS RV's. None of them ever experienced any damage from it.

Let's break this down real quick.

You start with a well equipped, good paint RV-10. Of most of the examples of that I've seen, you're looking at 1650-1700 pounds empty, more towards the 1700. I've seen several examples that are north of 1700. I'd like to think my RV-10 falls into that category, and it came in at 1695. I set my GW at 2850. I've never come close to that in real life, except during Phase 1.

Your pilot and passenger list sums up to 870 pounds. Let's not yet worry about where they're sitting yet. So, now, you're at 1700 + 870 = 2570. That leaves 230 pounds left for gas and bags (assuming a 2800 pound GW).

Let's talk about CG for a bit. Where your CG comes out at will be a huge factor in how you'd place the people in the plane. Mine initially came out fairly aft at 108.64". When I ran my expected CG scenarios, I found that I could easily get out of aft CG limits. I eventually moved my battery to the firewall to compensate. My CG is now at 106.69". I'm very happy with that setup and never come close to aft CG issues.

I ran your passenger scenario through my W&B spreadsheet. With 2850 GW, I could do your exact scenario with 40 gallons of gas (I conservatively flight plan for 13gph) and 20 pounds of bags. I'm still shy of my max GW (2826), but if I burned off 30 gallons of gas, I'm at the aft CG limit. If I shuffle your linebacker friend to the front seat, I can go to 44 pounds of bags and not come anywhere close to the aft CG limit.

Hope that helps some. A lot will depend on what your final empty weight is and where your CG comes out at whether you can handle the scenario you brought up. Building lighter is always better.

My plane was on the heavier side at 1703#, but I was very happy with the CG. Here is my W&B on the plane. You can play with the numbers to get an idea of the wide range of loading options the RV-10 offers. When I moved to a different hanger 100 miles away, I had the plane loaded to to the max with tools, tool boxes, and everything in a hanger I could fit removing the rear seats for a large cargo area. I also had full fuel. My wife and grand kids were watching when I took off. A Cirrus was ahead of me and I was second in line. My wife commented when I returned for more stuff that I took off in half the distance the Cirrus did, and out climbed it also!

N959RV Weight & Balance Data
Empty Weight: 1703 lbs. (8 qts oil & Wheel Fairings @ #3.75 lbs. each
Gross Weight: 2700 lbs.
Datum: 99.44" forward of wing leading edge
CG Range Limits: 107.84" - 116.24" aft of Datum
Fuel: 108.90" Aft of Datum
Pilot/Front Passenger: 114.58" Aft of Datum
Rear Seat Passengers: 151.26" Aft of Datum
Baggage: 173.50" Aft of Datum
Right Wheel: 688 lbs., arm 123.85", moment 85209
Left Wheel: 685 lbs., arm 124.15", moment 85043
Nose Wheel: 330 lbs., arm 49.90", moment 16467
Total Weight: 1703 lbs., moment 186719
Empty CG: 109.64" (moment divided by weight)

To Compute Loaded CG
Multiply weight by arm = moment
Add all weights
Add all moments
Divide total moment by total weight

Doh! I transposed a couple of numbers in the original version of this post. The scenario pictured below is for a 230 lb passenger, not a 320 lb passenger. In any regard, I believe my RV-10 represents the practical limit for RV-10 load carrying capability. It weighs about the same as Van's demonstrator and is better equipped. I'll retain the remainder of this post, since it might be helpful for someone else interested in maximizing load capacity.

I built my RV-8 and rebuilt my RV-10 with a real focus on load carrying. My RV-10 is well equipped, but weighs 1596 empty with a forward empty CG (106.94"). The key is determining your mission ahead of time and avoiding buying every accessory that will fit in your plane. My mission is IFR load carrying machine with a strong interest in efficiency. One other cockpit design driver for me is that my wife is also a pilot. We each have our own seat (I fly right seat) and the panel is designed for no-compromise PIC form either.

Key points:

1. I live in the desert, so no interior primer.
2. I have nice leather seats, but all other interior is Rustoleum Stone paint. My goal is for everything I touch or interact directly with to be very nice. My interior looks good, but not the premium car like padded cell so common in RVs these days.
3. I wear good headsets, so I have I have no interest in carrying a lot of soundproofing. For safety my firewall is insulated with fiberfrax and stainless foil, AKA the Dan Horton Method.
4. I have a lightweight composite 2 blade Whirlwind prop.
5. I have two EarthX lithium Iron batteries on the firewall. I have dual alternators supporting dual electronic ignitions and an all glass panel. I was able to swap a single Odyssey 680 battery for two EarthX batteries, a second alternator, and two extra contactors. This only added 1.5lbs and much reliability. EarthX batteries are a real game changer if they fit within your risk profile.
6. I have a fairly nicely painted airplane. I think the paint would be lighter if I had done it. The original builder had it done by a car guy and there was a lot of polyester filler sprayed on the fiberglass with attendant weight and poor adhesion.
7. Although I'm just within the cg limits when solo, unless I'm filling the airplane with people and stuff, I keep two 25lb shot bags in the baggage compartment. I believe Van's does this too. This makes the airplane fly nice when light, and still allows maximum loading flexibility.

Here's some photos:

Guy, I noticed you transposed the numbers for the male friend. You used 230 vs. 320 from the original post.

Auburntsts said:

Guy, I noticed you transposed the numbers for the male friend. You used 230 vs. 320 from the original post.

Click to expand...

Ha! No wonder it seamed so easy! I retract my statement and will edit my post above. Thanks for the catch.