Hi Jim..

Gunny uses a bit (hell, a lot) more of the grass runway than he needs to rotate out.. his beast gets up to flying speed pretty quick. He's done an outstanding job of paying attention to previous builders' experiences regarding incidence; so his trim requirements are darn near neutral. The weight of the bird is no handicap with the engines he's using.. the thing climbs out with authority when he pulls the stick back.

Pretty early on in the project I managed to talk him into cutting a new wing for it.. the one provided with the kit was pretty ugly with regards to the quality of the foam cutting. Unfortunately, I wasn't able to talk him into cutting one with a bit thicker airfoil, knowing he'd wind up a bit heavier than the 'prototype'' kit. He's a bit stubbon at times. As it stands now, around the kit's stock airfoil; the bird flies nice and slow and very stable with his flaps down at about 12 degrees or so. He's set 'em up as 'progressive'.. the inboard set droops a bit lower than the outboard at full deflection, and we expect it'll exibit no adverse tip stall in hard flat turns at low speed. I'd have used a bit thicker airfoil, but honestly can't fault the flying performance of the bird when 'dirtied' up a bit. With the wing clean, it flies pretty fast... and has a 'oh my' sink rate when he backs the throttles down below 70%. With some flap cranked in, he can fly quite 'scale like' at about 50% throttle.

Pilot-wise.. Gunny's a superb pattern flyer... and he's got a lotta multi-engine time on various models. The guy uses rudder without thinking about it.. a trick I'm still trying to get my forebrain to assimilate. I have no worries about him getting on the rudder the instant the bird exibits adverse yaw (engine out); meanwhile; he's got a healthy amount of aileron differential, and we cut those new cores with about a 1/4" of washout at the tips. The bird does tight, beautiful scale-like 'flat' turns with just a bit of cross-control.. just like I'd expect it to.

As it sits now.. and after looking at if (and harrasing him, arguing with him, teasing him and tormenting him) for damn near 3 years on just about a daily basis as he's worked this project, I gotta say he's done a spectacular job.. and it looks just as good from 3 inches as it does from 30 feet... inside and out. Truly; this is a remarkable scale modeling masterpiece.. all the more so, having endured the abuse heaped on him by myself and his other buddies throughout the project cycle.

Heluva Job, Guns!

Steve Anthony
NoBS Batteries
www.hangtimes.com

Guns, regarding the pic size.. when you clcick on the 'larger image' link below your photo's they come DOWN to screen size. Must be something 'weirded out' on the RCU post sequence.

There must have been a glitch last night in rcu.

Actually, I purosely build up a lot of ground speed prior to lift off. (a typical saftey margine for multi engine aircraft in case a flame out occurs) I know it will lift off a lot sooner and at a lower takeoff speed because on one of the taxi tests it went airborne to an altitude of 6 feet and I flew it for about 200 feet down the runway and landed. I did'nt want to get airborn but I had not much fuel left to actually fly her around. (I was spending about a half hour in tuning/synch'ing the engines).

Also, Steve has a good eye. The take off position flaps are 15 degrees, which I can putt putt around at about 3/8 throttle. With no flaps the plane does fly fast and will hold altitude at 50% throttle. At 49% throt. she will slowly lose altitude. Also my 4 bladed props are fine pitched so they are more efficient in a 4 bladed configuration. But with 15 deg. of flaps and some ground speed behind it and the engines turning at 10,500 RPM's she'll easily take off at a steep angle. The power of these OS .32 SX's and my 9x5 props are more than enough to handle this 22 lb bird (dry) Take off weight is at 23 1/2 lbs fulley fueled.

Landings: She slows down very nicley at a scale high angle of attack with no bad tendencies. Probably due to the -2 degrees of washout in both wing tips.

Gunny

Pic. 1. Repeat the steps for the 2 outer engine nacells. (see a few posts ago). You'll have to tack glue on some small aproxx. 1/4" thick temporary spacers to the frame's face on the outer engine nacells. This is because I moved my nacells to a more scale spacing. (Remember, the wider the spacing, the more reliable engines you'll need.) The taper difference of the wings LE from the main center section (the inner two nacells) to the two outer nacells is about 1/4". The nacell pockets will have some gaps and or may need trimming because of the outer panel (top of wing is flat/ bott. tapers up and the progressive twisting of the washout).

Remember. The wing has to be glassed, fully cured and scuffed good in the areas of the nacells, also inside and out of the fiberglass nacells before you tack glue nacells to the wing. I then use BVM aero-poxy to first put a bead of this thick/gap filling epoxy system all around the fiberglass nacells.

Pic. 2. After the epoxy glue has fully cured, This glue is lighly sanded to remove the shine and then I used about a 1" wide 2oz glass cloth both inside and out and all around the nacells. Dont forget to stuff some way in the back of the nacell too.

Later,

Gunny

Thanks Grinder for posting for everyone to see. Just info on the flying conditions we had a 90 degree cross wind 8 gust to 15 and with 3 engines on the landings you can see how difficult it was to make the "narrow" runway. The sound also gives a indication of how much wind was blowing. Jim

You are so right about this sink rate. If you land with full flaps and low power it will sink like a stone and land hard. I found this out on landing #6. Dropped in like a stone and some of the wing sheeting pulled on the edges at the foam. I had to slit the sheeting and pour epoxy into the area to seal it back. Now I land long and use power through the flare. I don't cut power until wheels touch.

I can tell Gunny is a craftsman just looking at his work. My bird now looks like the Vietnam era bird,, leading edge paint missing,, some belly scratches due to grass and Katrina hanger rash. But it still flies well. Hopefully #4 Saito.30 returned from Horizon will keep working on the next flights. Jim

The horizontal tail. Pics should be self expanitory.

Gunny

O.K. guys, Here's Gunny with a mini series of the construction of 4 bladed propellors such as the ones on my c-130.
To size props from 2 blade to 4 blades you must figure out which 2 blade prop works well with your engine/plane. For instance on my twin star and c-160 using os .32 glow engines I noticed a standard 10 x 6 wood props works well. So for a good starting point you simply drop the dia. by 1 inch and the pitch by 1 inch. Thus for the OS .32 engines a 9 x 5 4-bladed props works great. A couple of things should be kept in mind. Most people say 4-bladed props are very ineficient. That can be very true. The wake of the prop is 90 degrees from each other verses a 2-bladed prop who's wake is 180 deg. apart, thus given more time to clear the wake out of the next incoming blade. But in my studies and trial and errors I can give you my findings. A 2-bladed prop test should not exceed in a pitch of 8, because I noticed if a 4-bladed prop has too much pitch the wake turbulance is much greater and at 90 deg. the next blade is so fast in this turbulant "HEAVY" wake that it is not "BIGHTING" the air. The other most important factor is the width of the blade. A narrower blade contributes also less turbulant wake/ drag. The only two types of prop manufactures I like to use for 4-bladed props are Master Airscrew wood and Top Flite wood Power Point.

The last two pics. are flying props on my 1.20 size p-47 which is a 15 x 6.

Props are an important piece of an equipment on your aircraft. It must be manufactured in the utmost precision and craftsmanship. So, proper and accurate jigs must be built first.

Pic. 2. shows the 4-bladed alignment jig/clamp. In the center of this flat board is a threaded hole for a 1/4-20 bolt. On a common radius is 4 dowel alignment pins spaced 90 degrees apart. Use a compass and square to draw lines on this wood or on a piece of paper. The holes must be drilled on a squared up drill press.

Pic. 3. shows the prop/router holder. The height of the 2 sides are flush with the thickness of the prop.

Pic. 4. A high speed router and pic. 1 is the router bit. Look carefully at this bit. I've ruined props because of using different types, shapes, No. of flutes and diameters. This bit is ~3/8" dia. with 2 flutes.

Let's begin.

Pic. 1. Place the props down in the jig, rotate props so that the leading edges touch the 4 vertical pins and trace the curvature of the hub.

Pic. 2. Flip over and trace the back side of the hub.

Pic. 3. Lay the prop in the jig and clamp down. There's a dowel down in the prop hole going through the jig to hold it from shifting side to side while routering. The arrows indicate the direction of movement of the router tool.

Pic. 4. Get ready to router. The depth of the router must be set to half the thickness (+1/64" / -0" tollerance) of the prop blade.

Pic. 5 & 6. Saftey glasses on and router away slowly and carefully.

Pic. 7. Repeat for the back side of the other prop.

Pic. 8. Your part way their.

Stay tuned later, Gunny

Pic. 1. With a No. 60 drill bit and a dremel tool, You must plunge small holes in all the exposed areas you removed and the sides to a depth aprox. 1/16" deep (max.)

Pic. 2. Dry run fit. (make sure all 4 blades LE touch the pins and that the hubs are flush with one another. One can't be higher than the other.

Pic. 3. You will need the following; especially the vasaline, a large fender washer to cover the entire hub diameter and BVM AeroPoxy glue. A substitute epoxy glue can be Hardman white fiber filled thick epoxy glue from Wildmann graphics. DO NOT USE any other type of epoxy. These props are very hard and dense woods.

Pic. 4. Coat all surfaces with epoxy.

Pic. 5. Lay wax paper down and lube up the bolts threads.

Pic. 6. Lay wax paper on top followed by the washer and screw down snuggly but not so tight that all the glue oozes out. Allow to dry for 24 hours.

Pic. 7. Remove and inspect and file or trim away epoxy blobs. Scuff, paint and clear coat. After clear coat is fully cured, Throw onto a balancer and set one pair of blades horizontal. The lighter side gets a shot of more clear as required to balance. Then rotate 90 degrees to the other pair of blades and repeat balance. Then rotate 45 degrees so as your looking at a letter X and balance. The lighter side of the X gets a shot of clear on the 2 tips. The prop should balance throughout + & X at every 90 deg. position.

Gunny

Gunny,

Your plane is incredible. I like the way you built your own props, but I would be worried about prop failure.

DOes your back ramp work? I will begin working on my 132" Palmer 130 early next year. I plan to have my ramp functional, with paradrops. I found this site to supply my chutes.
http://www.aeroconsystems.com/chutes/index.htm

Thanks for sharing your build.
Mike

UkerDuker, For 4 years I have been using this technuique and not one has failed. If you have a slight prop strike then you must remove the prop from the enigine and thougholly inspect it, ie. bend it, twist it and check that none of the seams let go. If one has a slight seam crack, then just toss the prop out and make a new one.

My ramp on the C-130 is not operational, but on my C-160 it was and also had paratroopers jump out.
Gunny

Gunny the information and explanation on 4 blade props is simply great. It is a pleasure to learn from a real craftsman.

Bill

Grunny You are a true Craftsman. Thanks For all of the info.

I have been working on a C 130 wing, which does not have flaps.

Has anyone measured the minimum flight speed with a radar gun with and without flaps? Retro fitting flaps would be difficult but might be attempted if the speed difference was large enough.

Bill

Gunny,

Thanks for the great information on the props. I have already started building my jig. I'm going to try to cut mine with my vertical mill.

Gaines

Thanks for the nice compliments guys.

BillS, rryman (Randy) built his at 17 1/4 lbs and he does'nt have flaps and he says it even lands very good and is so pleased with it that he is not going to add flaps in the future. I guess if you build it under 17 1/2 lbs, then you probably dont need them. But I saw what I wanted to do and changed my mind totally around and decided to go "Heavy Metal" all out scale. Well, almost.

Adding flaps to finished foam core wing is much easier to do than to a finished built up wing. Been there both times.

gsmith6879, Great to hear it. On the vertical mill, get the spindel speed as high as it will go. Also, in your instance, because vert. millling machines dont get the rpm's, you may need a finer or 4 fluted end mill. Just remember, clean cuts, parallel slots and precision depths.

Gunny

Here's a vid i probably posted 40 pages ago but it's still worth another look. Palmer C-123 loading ramp. It's not mine but i think this vid is from another RCU'er on here. I plan on having a functional ramp on my Palmer 132" C-130

http://www.youtube.com/watch?v=LsRiUt5zgMU

Grinder.

Grinder.

On the cowls, I cut out one cowl around the engine. Then I pulled a clear plastic vacuume formed over one that has'nt been cut out yet. I take the clear molded cowl and pop it onto the one that has been cut out for the engine. Taking a fine marker I trace the cut out outline, remove and cut the clear cowl. Now I have a perfect template to pop onto the remaining 3 cowls and trace with marker, cut the 3 fiberglass cowls and wa la 3 identical cowls without guessing or trial and errors. I also added a 1/8" lite ply ring to the front of each cowl to stiffen up and close the gap between the cowl and back of spinner.

Gunny

Gunny,

Wouldn't it have been better to pull the clear cowl first and cut that, than to risk the fiberglass one? I have seen (in some kits) the clear cowl used as the "try" cowl and then it becomes the pattern for the "real" cowl(s). Just a thought.

Yes and no, but the clear one has been pulled over the original and thus larger. Also the bott. end of the pulled one is ragaddy so it really would'nt have worked well. Now on the kits the clear cowl has been pulled from the original "size" mould thus the clear and the fiberglass cowls are exactly the same.

Gunny

What are the wheel sizes for the 100 Inch Quality Fiberglass C-130.

I hate to do it but considering lack of time to build it and money needed for other projects my NIB Quality Fiberglass C-130 kit is for sale in the Twin / Multi engine section of the RCU for sale adds. I sure enjoyed reading these posts and will probably continue to but will just have to enjoy everyone else's Herk builds. Thanks
fossil