Empty weights

[Luked 71]

I guess I'll re-post the question I asked earlier today right before the site went down. Could anyone share some real world empty weights? Any additional information that relates to weight would be helpful too (engine, custom features that affect weight, etc.). I searched for this, but didn't come up with a similar thread.

 

Now that I'm about ready to start building my Avid, I'd like to set a weight goal. I'm guessing that I'll be somewhere between the 912 guys and the Subaru guys. That's assuming similar airframe to my MK-IV (Avid A-IV, or KF I-IV).

 

Thanks,

Luke D.

[Av8r3400 1179]

647# empty.

 

Kitfox IV, 912UL (80 hp), Grove gear, Warp Drive prop, 21x8.00-6 tires, molded windshield and doors

[C5Engineer 1170]

535lbs 582 blue head side and belly radiators. B model cowling. Very basic interior. No nav lights or pitch trim.

[Luked 71]

That was quick. Excellent! Thanks guys. Any others would be appreciated as well.

[akflyer 1427]

571# c model HH with wide gear, aluminum extended baggage, 26" goodyears, Airdale wide gear, too much crap in the panel, c box and Ifa prop. I have since removed the goodyears and lost 36 pounds.

[IFMT 36]

726#. Soob ea 81, airdale wide gear. 20 pounds ballast at the tail. Mark4 HH.

[marshawk 82]

#763 ea 81 soob in a fat avid

[dynomike 91]

740# Subaru ,21" tires , brs parachute

[tcj 150]

kitfox Classic 4.  503 Rotax.  First weight and balance was 547.  A couple years later I added PVC wing strut fairing so I reweighed and also decided to stop trying to fool myself and included the fire extinguisher, hand held radio, seat upholstery, baggage sack, hand held GPS and head set.  New weight is 573. 

[dholly 718]

I started a thread sometime ago hoping to collect W&B info for Kitfox model 4's.

My info is there > http://www.avidfoxflyers.com/index.php?/topic/1606-kf-4-1200-wb-comparison/

Edited 11 Apr 2014 by dholly

[ChrisBolkan 130]

Based on your question yesterday which was worded slightly differently than today, I wrote the following long winded reply. When I tried to post it, the site was down. I was able to click "back" and copy it to word pad so I could post it when the site came back up. Now that it is back up the question is a bit different (not stating your intended engine any more), but I will past in yesterday's reply anyway:

 

My MKIV w/582 weighed in empty at 587lb with full oil and no fuel. Empty CG was near the forward limit because the 582 is right at the max engine weight the airframe was designed to accommodate..

 

One of my friends has a MKIV w/80hp 912. He has kept it pretty light (relatively) at around 635lb, but this or even my 582 MKIV above are not light with respect to the wing loading on the original A, B, and C models (same wing size and shape)

 

Another friend has a stretched MKIV with 80hp 912 and he falls in the 670 range. That's not due to the stretch. It's due to the fact that he is one of those guys that if a little is good more is better. Everything on his plane is nice but exceedingly robust. He has learned his lesson and is working on a long term diet to bring his empty weight down. It performs well, but you can definitely tell the difference between it and the 635 LB plane.

 

Luke I know you don't know me and I don't want to start a war or make any enemies or come off as a know it all. However, if its not too late I urge you not to go with a continental or Lycoming engine. They are awesome engines and I understand the draw to use one. Avid designed a plane for these engines, the Magnum. I have one and LOVE it! But it has increased wing area, increased gross weight and different weight distribution to accommodate the larger engine.

 

The original Avids were just not designed for an engine that heavy. You will end up having to put significant additional weight in the tail of the plane just to counter the heavy engine. The plane you end up with will not perform like the Avid was intended to perform and feel. You will always be flying at gross weight.

 

Avids will fly at gross weight just like any other plane will. There are plenty of times you will fly at gross weight even in a very light Avid, like when going camping and so forth. But you will never be able to go camping because you and half a tank of fuel will put the plane near gross. If you never knew the difference that might be fine...just the way it is. But if you've flown and gotten used to the plane at gross and then suddenly switched to solo with half a tank of fuel in a plane that has 600LB of useful load, the experience is almost spiritual. You would be blown away and always be flying as light as possible except when carrying baggage to go somewhere.

 

I helped a good friend build a KF5. He was obsessed with air cooled traditional engines and used a 100hp 0-200. He ended up selling the plane because he was disappointed in the performance. It required something on the order of 20lb in the tail just to make forward limit W&B. While it flew nicely and was quite fast, it was a dog compared to another friend who had the same KF5 with just an 80 HP Rotax. The planes weren't in the same league of fun and overall performance even with the 20 hp difference. The 100 HP plane was faster, but in every other respect there was no comparison.

 

Please take my comments as input for consideration and please don't take offence. I have no stake in the game other than relaying my experience and wishing everyone end up in the best plane they can for the effort they put in.  

 

Chris

[Luked 71]

Hi Chris,

 

Thanks for such a detailed reply. I didn't post exactly the same thing as before, because I didn't even remember exactly how I asked it the first time. After I re-posted, I remembered a few things I had forgotten, but decided to just leave the simpler post.

 

I'd like to discuss the pros and cons of certified engines in the lighter Avid and Kitfox type planes. Maybe I should start a thread just about this subject. Quite a few people have listed their empty weights on this thread, and I think it could be a useful thread for the future if people just keep adding empty weight info to it.

 

No hard feelings at all about your advice. I welcome it. I've agonized over engine choice quite a bit already.

 

Luke D.

[akflyer 1427]

If its stock length then keep it light as possible in the nose.  If its stretched, then subies and other aircraft engines are viable.  I know there are plenty of guys with a subie in a stock frame, but I bet they dont fly as good as a light one.  What is your mission?  low and slow STOL work or ranging out CC ?  what your mission profile is will steer you towards an engine choice.

 

FWIW, I am trying to talk Bob into stretching his KF IV and putting a tuned up C90 in the nose.  A little work here and there and he will basically have an experimental Tcrate that will fit his mission profile perfectly.

 

[Luked 71]

If its stock length then keep it light as possible in the nose.  If its stretched, then subies and other aircraft engines are viable.  I know there are plenty of guys with a subie in a stock frame, but I bet they dont fly as good as a light one.  What is your mission?  low and slow STOL work or ranging out CC ?  what your mission profile is will steer you towards an engine choice.

 

FWIW, I am trying to talk Bob into stretching his KF IV and putting a tuned up C90 in the nose.  A little work here and there and he will basically have an experimental Tcrate that will fit his mission profile perfectly.

 

 

This was pretty much my thinking. I put some more details in a new thread here:

 

http://www.avidfoxflyers.com/index.php?/topic/2807-continental-in-avid-mk-iv/

 

Chris raised some really good points. I don't think he knew some of the details about my project (that it was stretched, or that I was considering the smaller Continentals for instance). His points are still very valid though. Good food for thought.

[BryceKat 125]

Weight is the enemy of movement. And I'm taking that personally by sheading the last 25 lbs of fat off me😳. My MkIv w582 started off at about 555 and is down to @525 and the difference is amazing in flight. If it's not absolutely for flight (wing spar, tail feather, etc),take it out in the driveway, hold it eye level straight armed for 15 minutes, then ask your self, "Based on had bad my shoulder is on fire, is this worth taking into the air with me?" Needless to say, there was about 30 pounds of shit left out in the driveway! Everything this subject now! Good luck!

[akflyer 1427]

Thats a pretty good way of looking at it!  On my last flight I noted that my VSI is not working.  It bugged me cause there was something in the panel that didnt work, but I have a VSI on my GPS that is damn near as accurate at the old steam gauge in the panel.  I was going to replace it, but now I think I will just huck it.  It would be nice to get the Avid back to bare bones as it is about to be my Sunday flyer and if I am going anywhere that weather will be an issue I will be using the 180.. Which has also gone on a diet (over 40 pounds of old ADF crap and the old HF antenna tuner etc.)  It will be loosing almost 60 pounds of interior as well!

 

The earthX lithium battery is high on my list.  I can loose 11 pounds right there.

 

[Bandit 286]

Avid Bandit with the 503 Rotax, Under 500lbs.

[SuberAvid 617]

This is a contest I don't want to be the winner of but afraid mine is...maybe at least until Ed gets his flying

[Luked 71]

Hey Randy,

When I started this thread, I was actually thinking, I hope this doesn't come off like I was saying the lightest planes are better than other planes. I just wanted to get a feel for what kind of weight I should realistically shoot for with my engine choice. Mine won't be the lightest either

For the record, your plane is one of my favorite Avids. It just looks like a bush plane, and it's demonstrated that it's plenty capable.

 

Luke D.

[Av8r3400 1179]

My buddy's Avid-Kitfox hybrid weighs 670.

[Luked 71]

My buddy's Avid-Kitfox hybrid weighs 670.

 

Which engine does he have?

[EDMO 1078]

The J3 is right at 800, and flies fine with a 1200 gw limit!   It flew with the C-65, but a LOT better with C-90.

EDMO

Edited 15 Apr 2014 by Ed In Missouri

[Av8r3400 1179]

Which engine does he have?

 

Rotax 912UL - 80 hp.

[birddog486 21]

For another reference I just finished the first Weight and Balance on my Model C tri-gear with 912ULS and extended Aerobat speedwing. Came in at 667# with a CG at 12.145

 

Travis

Edited 1 May 2014 by birddog486

[dholly 718]

^ How close to flying? I can't wait to hear the performance #'s on that one!