What is the lightest weight 0320 PA18 you know of?

[cobblemaster]

How much would a non electric 0320 powered PA18 weigh?

[Frank T]

Jim Richmond at Cub Crafters had a 160HP that he built a few years ago that weighed 903#. No interior, electric, or rear seat controls, and standard baggage.

[mvivion]

I flew a similar airplane, which had been rebuilt and all wiring, and excess "stuff" removed, including unecessary tabs, x bracing, etc. This was an early 135 Cub that had been converted to 150, and not sure they did the whole conversion.

Empty weight was 930.

Pretty impressive performer, but not much fun to fly around airports.

Mike V

[diggler]

delete

[RedBaron]

Not Very Much. :P

[Crash]

I would take what Jim Richmond says with a grain of salt when it comes to weight. A "Bush" ready PA-18 with an O-320 weighs between 1140 and 1170 lbs. If you have the light weight battery (13.5lbs) light starter (8lbs) lights, switches, and wiring, you're looking at around 50lbs if you removed them. This brings you in at around 1090 to 1120 lbs. Before everyone starts throwing weights around, "Bush" ready means...31" tires, borer prop, scott 3200, safty cables, extended baggage, bigger tanks, belly pod, tie down rings, long step, heavy duty gear, float fittings, X brace, under seat baggage and a few other things. Crash

[mvivion]

Crash,

Precisely correct, and the 930 pound airplane I referred to earlier lacked most of those things.

However, you are also missing the point that there is about thirty or forty pounds of other electrical stuff in one of these things, in the form of wiring, solenoids, etc. Interiors also weigh quite a bit.

Nonetheless, your point is very well taken. The airplane I flew had the old 25 inch Airwheels and an honest weight of 930, but as I noted, I don't think it was a legal airplane in retrospect. It had early wings, and I don't think it had the extra fuselage tubing required for the 150 conversion.

As you say, it may be possible to get there, but the airplane would not be very useful. The one I flew, I spent a lot of time worrying about stuff falling, slipping or sliding into some part of the airplane, never to be retrieved.

Another key element that this airplane had was virtually NO silver dope on the fabric, so he was looking at recover soon, and kept wing covers on all year.

Now, that's practical.

Mike V

[Dave Calkins]

I weighed the fabric stripped from a wing I redid after our windstorm.

Stits with a THICK topcoat of Aerothane. Not the best for long finish/fabric life or light weight, right??

Well, the stripped covering weighed only 9.5 pounds!!!

The point is that a guy isn't saving much weight on a "lightweight" airplane by cutting out several "film-thicknesses" of silver dope.

Another point, I'd be interested to hear what you guys going through rebuild have for interior weights. Please weigh that pile of interior panels and let us know what you got.

The fabric interior panel idea is looking really good to me. Lightweight, repairable, Inspection access can be placed anywhere you damn-well want, removable for a major look-see, keeps Mike V.'s minimaglite and pencils from slipping back into the abyss. Still, aluminum panels may be the best "all-around" or "bush-ready pick-up" choice.

Crash, weren't you finished ever using safety cables again?? That would save a few pounds.

Dave.

[cobblemaster]

Would it be realsitic to build a basicaly stock PA18 with no electric and 850 tires for under 1000 lbs? Only options would be X braced cabin and tail. No ext baggage or under seat baggage. Would have metal interior with no headliner.

[S2D]

Nonetheless, your point is very well taken. The airplane I flew had the old 25 inch Airwheels and an honest weight of 930, but as I noted, I don't think it was a legal airplane in retrospect. It had early wings, and I don't think it had the extra fuselage tubing required for the 150 conversion.



Mike V

150 conversion I am familiar with doesn't require 16 rib wings or the extra tubing in fuselage. extra ribs are for increase in redline and extra tubing is for increase in Gross Weight. Neither are "required".

[HydroCub]

I saw a 180 hp Cub in northern Minnesota a few years ago that weighed 980#... with 8.50 tires and Borer prop, but no electrical system. You talk about performance..!!! It would not stall with full power, full up elevator..... just mush along indicating ZERO airspeed. I think the owner eventually 'tweaked' his elevator travel to make landings easier when solo.

[cobblemaster]

Hydrocub, good info, thats what I was looking for. I think the square tail feathers would be a good idea on such a plane.

[HydroCub]

Hydrocub, good info, thats what I was looking for. I think the square tail feathers would be a good idea on such a plane

I agree as the Cub lacks good elevator authority with a heavy front end plus one pilot. But don't forget that you need to be very cautious as that cg moves aft. I intend to get my empty cg as far forward as possible and live with the risk of the tail being light when solo. Am even considering an attach point for some weight on the tail for bush-type ops when light. The forward cg will give me lots of ability to load the aircraft rearward for travel, hunting, etc. You should consider adding some area to the rudder also... I'm extending mine aft to pick up >150 square inches of surface area.

Weight is critical if you want performance. Strength means more weight, so you have to figure what you really need. If you are going to beat it, make it strong. Otherwise, you cannot make it light enough.

[Bob Breeden]

Hydrocub,

Interesting that you mention a tail effectiveness when lightweight with no baggage and solo. When playing, with little gas and nothing in the plane, I like to put a full 3/4 gallon water bottle, which would normally be on the floor where I could reach it for a drink, back at the very back of the extended baggage area.

That little bit of water weight sure makes the tail perform better at low speed and when drawing the nose up in the flare.

Bob Breeden

[SuperCub MD]

If you build light enough, I don't think you will need monster tail feathers. Use the lightest tailwheel and springs you can get away with, (learn how to land and take off with the tail always slightly up, and you won't have to bolt a truck tire back there). Anything you bolt back there that is even a little bit heavy has a loooong arm, and screws up the handling.

If you want to be light, the only electrics should be the mag switch and two p leads. Don't forget to take off the flywheel and spinner. Fabric interiors are a lot lighter, but you are constantly fixing holes. The best compromise may be a fabric interior with some very thin gauge aluminum panels glued on to the fabric in strategic locations for wear resistance.

The 13 rib wings are just fine, with no gross weight restrictions that I know of compared to the 16. And the 13 rib wings are lighter of course, some say they even fly better...

People always talk about the old frames being lighter. There are 4 short 3/8 .028 inch tubes at station 131 in the later frames that give it the gross increase. These tubes weigh next to nothing.

(Sorry, had to edit, had the tube size wrong.)

[Dave Calkins]

All interesting stuff, guys.

Consider that us guys in Alaska must by state law carry a "few" items as survival gear. A Cub presently under refurb I know of will carry its survival gear package very near the jackscrew at the extreme aft end of an extremely long upper baggage shelf. This will keep the tail from being light when unloaded and light on fuel.

Anyone have weights for a metal interior panel set??

Anyway, I figure about like Crash. A work or backcountry play-ready PA-18-150 usually averages, and flies great at: about 1150 pounds, in my experience.

DAVE

[HydroCub]

Anybody know what the 'widebody' Cubs are weighing when completed with electrics + VFR stuff.?

[cobblemaster]

Why did somebody invent the large tail feathers? Was it just a sales gimmick or just easier to manufacture or do they work a little better?

[Dave Calkins]

Here I am, back at home on the computer. I should be sleeping on the ground tonight preparing to drop a moose in the morning.

I just got landed back at Hood after I passed up a shot tomorrow morning at several nice bulls that my present airplane isn't light enough to get near enough to haul, and I'm not willing to freight them out by foot the 1500 feet of altitude back to a landing zone safe for my a/c.

Next year I will have a light Cub that will do the job.

Anyway, maybe tomorrow I'll find a few animals at lower altitude or easier (more in the performance range of a fat -14) landing zone.

The 4" widebody Airframes, Inc. fuselage is claimed to only be several pounds more than their stock cub frame. It'd make a great substitute for a guy who wants the elbow room of a -12, but the performance of an -18. At least one guy running one in "real" Cub territory likes his, and he built it for light, high altitute, crazy, professional, extreme, precise, you-better-be-right conditions.

My understanding is that the large, squared off tailfeathers (Sullivan) get the tail working again at the slower speeds the Cub is capable of when light and with extended wings.

The -12 with slatted-extended-increased incidence-Maule wings on it that I covered tailfeathers for last winter has elevators that appeared stock in shape, but the elevator span was slightly increased and the trailing edge was pushed slightly aft. All this was done in a curve, so the tail retains the curved look. INterestingly, the rudder was stock, and seems to be plenty effective, even with the extended Maule wings and very slow flying speed claimed by the owner and others on this site who have seen it. I've yet to fly it or see it fly.

So, there IS a use for an airplane like the one we're talking about.

I would have used it about 2 hours ago to get very close to a couple of Bulls and the harem one of them is trying to keep.

I've always talked about a "light" Cub.... Never have I wished for one so much as I did tonight when I dragged that teeny little piece of firm ground near these rutting bulls....only to fly home knowing I can't get close to them.

Dave.

[SuperCub MD]

Would it be realsitic to build a basicaly stock PA18 with no electric and 850 tires for under 1000 lbs? Only options would be X braced cabin and tail. No ext baggage or under seat baggage. Would have metal interior with no headliner.

Cobblemaster, forgot to answer this. This is basically my Super Cub, but I do have a metal interior, extended baggage, and all the other above mentioned "bush" ready goodies except for the belly pod, and I have stock fuel tanks. Wearing a set of little 8.50's or straight skis it is comfortably under 1000 pounds, (this is on certified scales, not BS). Pay close attention to weight while building, don't put in anything you don't need, and it will be light. On the square tail, put Micro VG's on the stab of a stock tail, and you will have more than enough control authority without the extra weight.

[cubdrvr]

Hey Mark...........don't forget that 30# BF Axe........... :lol:

[SuperCub MD]

Yep, I should have seen that one coming....But hell, I could put a whole stack of BF axes, a couple chain saws, and a whole case of CR in my Cub, and it would still be lighter than yours....And it helps to hold the tail down....Like I said, don't put in anything you don't need. And I need the BF axe (for intimidation, if nothing else).

By the way, thank for sending the pics from your trip, really wish I could have gone along,...someday... Been throwing lead at any birds yet?

[cubdrvr]

Patiently waiting...........reports are that this year SD could have the highest pheasant population in the past 40 yrs. Maybe we could have a fly-in hunt for some of you boys that might be interested. Leave your gun at home Boz........you get to throw axes and chase cripples ( oops, I mean flight challenged)

[Crash]

Dave Calkins reply: Dave I did think about skippimg safety cables a while back. I haven't seen any broken axles or short legs since H.D. gear and legs came out years ago. I talked with Steve at Atlee's, we said there were two or three guys the had gear collapses last year due to the 5/16" bolt that attaches the short leg to the hydrasorb shear off. A friend of mine had the welded end of a Univair hydrasorb come off, bad weld, collapse.....Safty cables save all of these aircraft. The problems have been lessened, but this gear design is still not perfect, so yes, I am running Atlee Dodge safety cables on both of my Cubs. It's cheap insurance. Crash

[cub_driver]

Dave

Where did you see those Bulls at I would just like to take a look :wink:

Cub_Driver

[Dave Calkins]

Come see me tomorrow (Monday) at Hood. We can go together, then I can fly cover..

Heck, I'll just PM you and we can talk.

DAVE.

[RMREBOB]

Has anybody investigated the use of carbon fiber/honey comb floorboards and/or interior panels? We use a lot of graphite on the race cars we bulid here and it is hell for strong and almost weightless.

[Dave Calkins]

Have seen plenty of metal honeycomb and also foam/glass-sandwich floorboards. Yep, they're light and strong...be careful, though, not to crush them with mounting hardware and rudder pedal brackets, etc.. Seems like lately people are back to plywood (heavy compared to honeycomb, but cheap), or plain old aluminum or diamond-plate aluminum (heavy?).

I've seen thin sheet fiberglass laminate used for interior panels and don't like it at all. It's not all that light compared to aluminum, kydex plastic, or especially fabric, and seems to crack and splinter plenty. Any of these materials are a compromise in some way. Seems like going down to maybe .016 2024-T3 Alclad might be the best compromise for interior panels. It'd be tough to poke through it and get to the exterior fabric, and it'd be approxiamately 40% lighter than .025.

Dave.

[csch]

The weight of an aluminum interior is 10 lb 12 oz that is including the wing root panels. How important is the undercoating material Piper put on the back of the panels? Looks like the undercoating material keeps the aluminum from rubbing on the tubes and vibration down, however must be a pound or two in weight. Is their something better and lighter than undercoating material to put on the back of my new panels? I have all the original cotton fabric from my 1955 cub and will weight it and post the wt. My first post on this site and not so sure of what I'm doing.

[K.S.]

A great first post!!! Could you please itemize the aluminum parts you weighed. Thanks.

[Dave Calkins]

Thanks for the info., will be interesting to find the weight of that cotton, too. Yes, what pieces does your interior weight include, and what thickness sheet was used to fabricate them?

A ttthin bead of silicone does a good job of keeping vibration between panels and tubes minimized. Also, a layer of electrical tape on the tube works fine. Nothing high tech.

Welcome aboard, Craig.

[csch]

weighed interior panels as requested, I will go clockwise around the interior listing the weight of each panel, right front 1.5 lb, under door .8, right rear 1.7, rear of baggage 1.8, left rear 1.1, left side 1.9, left front 1. and both of the upper panels that the fuel gauges are in, weigh 1. lb or .5 each. This is a total wt. of 10.8. All panels were stock, panels all were .025 except the one in the rear of the baggage it was .035. My 1955 PA-18 150 left the factury with a log book weight of 1013 and a gross wt of 1950. This was with no landing lights, just nav lights, no radio and a narrow deck that I understand is lighter than a wide deck.