Is my Mk4 a little too chunky?

[fusionfab 14]

So I did the W&B lastnight for the first time owning the plane. It's an MKIV #1017D. 

I have the document from its previous weights and used to be 675.5 

changes I've made - exhaust, cooling system, single carb and manifold, proper cowling. Quart of paint.

her new weight lastnight was 679.5. However I added a gallon to each wing and ran it about 10 minutes. So am I to remove ALL fuel? 

The new limits I came up with are 

EMPTY (<2 gallons fuel) - 11.71"

1 pilot +5 gallons -12.78"

Pilot/Passenger/22.4 gallons -13.36"

any thoughts on these numbers and adjustments I should make to get optimal performance? 

[akflyer 1427]

She is 120 ponds heavier than mine.  What do you have in the nose?  I would start adding some weight on the tail spring and get the CG back to around 15 or 16" to start with.  It will fly much better even though its pretty chunky to start with.

 

 

[1avidflyer 1983]

My MK IVs with a Jabiru in one and a 582 in the other weighed 585 lbs.  Do you have a Subaru engine?  JImChuk

[EDMO 1078]

Where is your battery?  A 15 lb battery about where the vertical stabilizer front is located will make a lot of difference.  I think some Avids had an access panel underneath in that area.  Baggage will make a difference too.  That <2 gallons (<12pounds) of gas won't make as much difference as the variable weights of pilot and passenger, although you continue to use the FAA 170 lbs for each on paper.   I like to make a separate, private, W/B using the actual weights, just for my info, since my passenger weight may vary by 100 lbs or more.   I weight about 170 lbs, and my normal passenger weighs 136 lbs, and a grandchild may weigh 40 lbs, but my CFI weighs about 230 lbs.  EDMO

Edited 29 Nov 2016 by EDMO

[fusionfab 14]

Sorry I should have mentioned that it is a Subaru EA81, single carb custom intake manifold for the fwf. 

There is also 10lbs of lead in the tail that I was hoping to replace with a small access door and survival kit as mentioned on here previously. 

I haven't weighed the battery but it is much more than 15lbs and is located about 24" ahead of the tail. 

I didn't use the 170lb number I just did actual weights of 205/135.

[EDMO 1078]

Your 205/135 averages out to the FAA 170 lbs each.  I have the Soob 81 and that is why I extended the leading edges on my wings 4".  I flew a Kitfox 1 with a Soob, 2 wing tanks, small tail and a heavy battery where yours is located, but for "optimal" flight, you need to get the flying CG back to about 16" or so.  EDMO

Edited 29 Nov 2016 by EDMO

[fusionfab 14]

So I should get pen to paper and figure out how much weight I need to add to the tail? I won't be able to move the battery back and farther but I'm going to do a second WB tonight to double check all numbers. 

[EDMO 1078]

So I should get pen to paper and figure out how much weight I need to add to the tail? I won't be able to move the battery back and farther but I'm going to do a second WB tonight to double check all numbers. 

I would try to pack in as much baggage weight as possible before adding weights to the tail.  I moved my header tank and both fuel pumps back another bay from rear of cabin.  EDMO

[fusionfab 14]

So I should get pen to paper and figure out how much weight I need to add to the tail? I won't be able to move the battery back and farther but I'm going to do a second WB tonight to double check all numbers. 

I would try to pack in as much baggage weight as possible before adding weights to the tail.  I moved my header tank and both fuel pumps back another bay from rear of cabin.  EDMO

ok should I weigh all the baggage and subtract that in fuel? 

[EDMO 1078]

So I should get pen to paper and figure out how much weight I need to add to the tail? I won't be able to move the battery back and farther but I'm going to do a second WB tonight to double check all numbers. 

I would try to pack in as much baggage weight as possible before adding weights to the tail.  I moved my header tank and both fuel pumps back another bay from rear of cabin.  EDMO

ok should I weigh all the baggage and subtract that in fuel? 

Not sure what you mean - are you pushing max weight?  Fuel puts you closer to rear CG.  Unofficially, you have no max weight - talk to Akflyer Leni  or Suberavid Randy privately about that.  They know more about your bird than I do.   EDMO

[Av8r3400 1179]

Less than 700# for a Subaru powered Avid is pretty good, IMO.

[EDMO 1078]

Less than 700# for a Subaru powered Avid is pretty good, IMO.

Agree - Mine will probably be 100 lbs heavier than your "Chunky".  EDMO

[lostman 198]

Pursang was placarded at 690 but I believe it was likely more around the 750 mark. The panel alone weighed close to 20 pounds with everything in it except the radio. I'm fairly certain that many things had been added to it after it was weighed. I know the gear went from 5/8 to 3/4" thick, that had to add weight. I also know there were several patched tubes and added brackets in places as well as a floor that was almost 15 pounds alone. 

The performance was still pretty good with a Warp Drive three bladed prop. 

[EDMO 1078]

Pursang was placarded at 690 but I believe it was likely more around the 750 mark. The panel alone weighed close to 20 pounds with everything in it except the radio. I'm fairly certain that many things had been added to it after it was weighed. I know the gear went from 5/8 to 3/4" thick, that had to add weight. I also know there were several patched tubes and added brackets in places as well as a floor that was almost 15 pounds alone. 

The performance was still pretty good with a Warp Drive three bladed prop. 

If I remember right, you flew the Pursang (aka Airdale) loaded up with everything but the kitchen sink - maybe that too!  Ha!  EDMO

[fusionfab 14]

I went to do WG again today but the scale went outta whack on me where it would return to zero and start at either above or below zero even after redialing. My local farm store has a heavy duty digital one that'll I'll pick up in the next couple days. 

I ran her near dry today so I'll do it with the slight Amount of fuel in it, and I'll also need to add a battery bracket in the tail that I forgot I still need. 

[lostman 198]

I went to do WG again today but the scale went outta whack on me where it would return to zero and start at either above or below zero even after redialing. My local farm store has a heavy duty digital one that'll I'll pick up in the next couple days. 

I ran her near dry today so I'll do it with the slight Amount of fuel in it, and I'll also need to add a battery bracket in the tail that I forgot I still need. 

Why not go ahead and drain the fuel so you actually know it's empty? It would be well worth your time so you have a known data point instead of just close to. 

Pursang was placarded at 690 but I believe it was likely more around the 750 mark. The panel alone weighed close to 20 pounds with everything in it except the radio. I'm fairly certain that many things had been added to it after it was weighed. I know the gear went from 5/8 to 3/4" thick, that had to add weight. I also know there were several patched tubes and added brackets in places as well as a floor that was almost 15 pounds alone. 

The performance was still pretty good with a Warp Drive three bladed prop. 

If I remember right, you flew the Pursang (aka Airdale) loaded up with everything but the kitchen sink - maybe that too!  Ha!  EDMO

Ed, I did have it loaded up pretty well when I first picked it up. After that I only flew it with emergency kit and whatever I needed to have with me for the flight. Honestly it never seemed to make that much difference in the way it flew. 

[fusionfab 14]

Yes sorry the wings are completely empty. By near dry I mean just a slight amount in AUX tank. Maybe 1/8 gallon. 

Lostman - do you know your CG numbers off hand? 

[fusionfab 14]

Picked up the scale at the farm/Ag store and have to completely start over. The previous weight I got of 679.5lbs is out the door. The weight I got from this scale is 722 lbs. 

At first I was concerned because the previous owners empty weight was 675. But, the first scale I used gives a much lighter weight when its not dispersed evenly across the platform. Weighed a 90 lb dumbbell (I knew I'd eventually find a use for it) standing it up and gives me a 20-25 lb lighter reading. Todays large digital scale measured the dumbbell at 89.8 no matter how I positioned it. So sadly I am confident that I now have correct numbers and she ACTUALLY weighs 722 lbs. 

Meaning my new numbers are 

Empty -11.20

Min. -12.21

Max -12.91

So now what...

Edited 1 Dec 2016 by fusionfab

[akflyer 1427]

You are blocking the tail level right?

[fusionfab 14]

 

Yes, tail raised level front to back and tires shimmed so level side to side. Plumbbob measures 1.5" from center axle and 144.5 from rear tail wheel plumb bob 

 

[lostman 198]

Yes sorry the wings are completely empty. By near dry I mean just a slight amount in AUX tank. Maybe 1/8 gallon. 

Lostman - do you know your CG numbers off hand? 

I wish I did. I'm not sure I even have that information here anymore. I'll look and see what I can find. Since the plane is in pieces and 2,400 miles away from me I haven't kept track of the paperwork for it. I'll look through a few things and see what I can find though. I'll post it up if I find it. I only had the plane for about a month before it was destroyed.

[fusionfab 14]

Yes sorry the wings are completely empty. By near dry I mean just a slight amount in AUX tank. Maybe 1/8 gallon. 

Lostman - do you know your CG numbers off hand? 

I wish I did. I'm not sure I even have that information here anymore. I'll look and see what I can find. Since the plane is in pieces and 2,400 miles away from me I haven't kept track of the paperwork for it. I'll look through a few things and see what I can find though. I'll post it up if I find it. I only had the plane for about a month before it was destroyed.

oh no worries lostman. I appreciate the help and am sorry for the loss. I've come to the decision, after looking for anything that can be sparred or moved won't be happening. My only option is to search for a smaller or at least lower profile battery and modify the mount to position it aft another 8-10" which should bring my CQ to mid 13 for min weight and low to mid 14 for max weight. 

[donhallwr 34]

Fusion,  attaching an Excel spreadsheet I've used for my W&B.  My Bandit is a tri-gear, couldn't tell from the posts if you have a taildragger,but with the numbers, I'm assuming it's a tri-gear.  I also have 10 lbs of divers weights in the tail section, which put me on a trimmed level flight (finally).  You can change the weights and numbers in the spreadsheet and it'll reflect the new CG.  My wheel weight was with empty tanks, but you can enter the numbers to reflect any amount (6lbs/gallon) you have in the tanks.

Don

WEIGHT AND BALANCE 54VH.xlsx

[nlappos 413]

Here is my Weight and Balance on S/N 1174D, a MK IV, it is a pretty standard MK IV with a 582 blue head, and one fuel tank in the right wing. Built by Jim Peet, who paid close attention to weight!

LAPPOS N4052X Weight and Bal.xls

[fusionfab 14]

It's a taildragger but has an ea81 engine and a 10lb weight to the tail. 

Thanks for the info guys I'm going to look over them now. Much appreciated