I've always had a bit of an interest in the Old Timer designs, and when fellow PhlatClub member Chuck asked for my assistance on this project, I just couldn't pass up the opportunity to work on one!

After Chuck and I kicked emails back and forth, we finally got to speak on the phone for a brief spell and he explained this project to me in greater depth. It seems that his flying buddy, Richard Stultz, also shares an interest in Old Timer designs, having built the original Lanzo Bomber from Chet Lanzo's plans. Richard captured the beauty of this plane in foam after scaling it down 50% and building one from 6mm Depron (pictured below). Chuck and Richard both told me that the plane, with a 1300kv Blue Wonder, flies incredibly like the original! It's really hard to believe that a little Blue Wonder can power up a larger aircraft like this, but they have assured me that it does so with ease.

Last week I got a phone call from Richard so that he could explain the aircraft in a little more depth. It turns out that Richard has been playing the RC game for quite some time, and in addition to the RC hobby that he and I share, he's also an avid motorcyclist! In the package he sent to me, he included a picture of his BEAUTIFUL Honda Valkyrie! LOL Chuck, I envy you for having such an interesting and capable flying buddy!

Anyway, Richard sent me a very comprehensive set of drawings that he had worked up along with a CD full of images from their original foam Lanzo Bomber. From these materials I was able to work up the files that are attached here. Had it not been for the completeness of his materials, I would have had significant difficulty working this project up! Got any more cool stuff for me to work on for you, Rich? :mrgreen:

With a sizable scale drawing in hand, I set out to recreate this plane. Now the question arose "How in the world am I gonna get this in SketchUp?". EASY! I took his posterboard drawing and figured out how many times I might need to scan this thing on my trusty old Dell 310 scanner/printer. I then drew tic marks and scales on the drawing in several places and scanned the thing in segments making certain to capture the tics and scales in each scan. I was then able to import each one into it's own SU document and scale it to the proper size. Once I had all of these separate SU files completed, I started copying and pasting them into a single SU file where I could assemble them (one for the Fuse, one for the wing, and one for the horizontal). After the hard work was all done, then the fun and easy stuff started - redrawing all of the parts.

I actually surprised myself on this project. From start to finish, this project only took about 2 hours to complete, including the time to draw the tics and scales and scan the drawing!

Chuck advised that he has some difficulty in running FFF on his MKII (bummer), so he prefers 6mm Depron. He asked that I lay the parts out to compliment sizes available for that material and I was able to accommodate him without any problem. Our buddies over at RCFoam sell 6mm Depron in sizes of 13" x 39" in White and 15" x 39" in Gray. I figured it best to lay the parts out to the smaller size so as to not limit his processing the files to Gray Depron only.

So here we have it - the fruits of my labor and fun! The design will require you to use 3 sheets of 6mm Depron no less that 13" x 39" (34" cut length on the X axis). The PhlatCodes allow for 100 IPM feedrate (my preferred speed when cutting Depron), V-Tabbing at 10% Depth, using the stock 1/8" PhlatBit. I can see no reason why you cannot cut this thing out on FFF, but that wavy substrate will lessen the beauty of this fine aircraft.

As is usual with my file packages, I have included my COMPLETE package including the scans, my rendering, PhlatCodes, and SU files along with a picture of Chuck's finished plane. Please note that there is a large triangle also included in the parts - that is a polyhedral fixture to aide you in setting up the proper angle for the polyhedral wingtips (you'll have to sand in the angle on the tips before you glue it up). Oh yeah, one more thing - I have also tabbed and slotted the fuse-side braces so you can put them in straight the first time, as well as the mounting plate for the wing.

ITEMS NEEDED FOR COMPLETION

3/16" Dowel for joining the elevator halves
3/16" Dowel for the wing hold-down pegs
24" length of Carbon Fiber tube to brace the wing (butted against the Kf step)
1 3/4" square piece of ply (I suggest 3/16") for the motor mount
Tape for the hinges
#64 Rubber bands for the wing mounting
Your favorite glue

I'll let Chuck chime in on his preferred electronics and landing gear...

Chuck and Richard, thanks for including me on this great project! As soon as I get a fresh supply of Depron, I'll be cutting one out for myself! I think this is gonna be a hit with those folks looking for a relaxing Sunday flier. Attached files Lanzo Bomber.zip (8.7 MB)Â

 

These files are set up for your regular ol', run of the mill PhlatPrinters.

 

Looks great Crash.... I love the look of old timers, but just don't like the way they fly. I do have an 8 foot Spook that I built back in the early 2000s. It's powered by a dewalt drill motor on a belt drive. I haven't flown it in about 5 years. Sure did draw a lot of attention at early electric meets as it was by far the largest plane there. I keep meaning to do a smaller foamy version as I just love the way it looks; inverted gull wing, but never got around to it as it flew like a truck

A buddy of mine has a plane he designed using the cardboard template method that he want's me to convert to cut files for the PP.... I'll have to use your method to get them into Sketchup....

 

Forgot to me mention/ask this in my earlier post.... Shouldn't the 1/2 sheeting on the wing go on the bottom? Or doesn't it really matter?

 

Looks great, good draw-up on a great plane.

I've had a few but the last Old Timer I had, I lost because I fell asleep That should give an indication of the ease at which they fly. I'm a tad more partial to the Playboy series though but in general they all fly about the same.

Was this a straight scale down? Or did you bump the chord up a few % to help keep the floatiness? Just wondering because if I recall the original Boomer was a big-ish plane around 100' span, around 1200 squares with a typical loading around 10oz/sq²ft. with modern FM equip. At 50% we are talking a 45' span, 300 sqr-in and a 'float about the same' loading around 5oz/sq²ft. which would put this at a 10oz(or so) AUW. Yep, it works, I'm just typing out loud .

The KF foil has my interest on a OT design, I'm used to doing it on a more slipper design like a flying wing. I'll give Chuck a PM about the flight envelope soon. From the look of it so far I may use this as my newer students first build instead of the foam LazyBee, which is nice but has issues in the wing.

Edit to add: i just check the file and answered my question

 

I cut one out of fff and my student built it in short order. Substituted a 1/8×1/4 bass wood spar to stiffen the wing. Since fff is not as stiff as Depron it also needed some bracing along the fuse.
All he had for motors were the two common sizes in the TowerPro flavor, the 2409 and the smaller one that likes a 9x4 on 2S. He had mounted the smaller one but the CG was at the TE so on went the big one Of course that 2409(?) will puff his little 2S-1000 for lunch so on went a 3S-1250 and a low draw prop in the 10x4 neighborhood.

The rest of the equipment was typ HK stuff including the cheap 2.4Gz 6ch system that has been flawless since day one. Good and lite with a satellite on the Rx.

The CG was now about 50% and that's cool with a Lanzo Bomber from my experience, and the auw was way over my wishing for weight of 10oz. It was now 15+.Which brings its loading to close to 8oz/ft*2. Well no turning back now,so into the wind it went.

Well, where do I start. it flew and from a stability point of view it was very good. In a large area you'd have to try and crash it because it just likes to be upright, as it should because its a free flight design. Now my over weight beast flew like a truck taking a fair amount of airspeed to act normal. so in a way it flew like planes did back in the day. One has to be 50' ft ahead of them. I even hit a tree that I've never hit in all the years I've flown here because I'm used to the quick directional change and trust/weight ratio of a modern foamy. No damage BTW

Ok, on to the glide ratio,,, is a negative ratio possible? I didn't think so till now. It doesn't take much power to fly but with no power it falls at a 1:2 ratio at best. I've never seen an airplane with that kind of aspect ratio fall that fast with zero flair possibility. A lighter model I'm sure would do better,, somewhat, I hope.

I suspected the airfoil was the issue so I strapped on my little Cermark Dragonfly wing and into the wind it went. I was correct.

So this little KF version of the Bomber is a great stable trainer for learning landings and all the close in turning and maneuvering one needs to know before moving onward. It's cheap and simple to build, handles the wind well and it easy to keep visually oriented. It's now my new student first trainer design. Thanks Crash, Chuck

 

I agree, and suspected issues early, more on airfoil than CG . If I was thinking of building for personal use I too would of done things different. But I'm an instructor per se and my goal is to teach design and flying traits along with flying skills. With the fabrication and time required for completion making the mod first would of removed a good lesson.

If my student chooses to pursue the design I will do mods to lengthen the nose, add to the chord, and doing a hollowed KFm-3 foil. Or at minimum, mod the current foil to a true KFm-2.

 

Since no one answered this one, and it seems to glide like a refrigerator, what if the 1/2 sheeting were on the bottom? This would hopefully give the illusion (to the air anyway ) of an under cambered airfoil, which I believe the originals were.
Just a thought.

 

Like this? Maybe this wing would work better..?

Attached files

 

'rcav8r'

The KFm-1 is the bottom step variety, I would guess at the speed we are looking at to 'float around' at,(i.e. 5-10mph) it would yield similar results.

'7up'
The open camber design is truly a floater, especially as one nears the 4-40 rule (4%arc peaked at 40% chord). But there is a major flaw in the design as far as structure rigidity during outdoor type flight loads. If anyone else built the FoamBee with the same setup knows any airspeed over float it goes nose down. Basically the wing twists as speed or AoA increases, low pressure lifts the trailing edge and it is amplified as it moves outward (angel of change that is), at that point it becomes almost an induced oscillation ride between pilot and plane

The fix for my FoamBee's were to sheet the bottom of the wing. No more twist, lot stronger, much less oscillation. But still not free flight stable imo.

My shot at the fix to get the foam bomber to float is going to look like this. I will add tape the length of the wing to bridge the steps. Should help act like a turbulator spar. Bottom step installation is the last resort. If that foil is nfg I'll just do it old school. The test I did with the smaller Dragonfly wing http://www.rcuniverse.com/magazine/article_display.cfm?article_id=436 was good and thermal-able(? ) even though it's a third less the area, and put the bomber at an 11oz loading, that's kind of is high for a draggy floater but I had no trouble hooking lift. My normal auw for my BL modded D-fly is 8oz for a 6oz/ft*2 loading and it floats like a dlg for the most part.

yes, I will get pics next session Attached files

 

Apparently I have to do some research on the KF airfoil ... I didn't realize there was such a thing. I was just thinking that it was simulating an airfoil, and the one on the drawing ( at least how I saw it) was giving it sort of a negative under camber - so to speak Hence the stated glide ratio of about 1:2

 

THANKS Yep saw that thread when I did a search after someone here posted about the KF airfoil... WAY too much reading for me to do right now thought . Will have to wait until the weather changes, and I have some more free time.

 

''As a matter of fact, kill the power at 1000 ft and you might be surprised how long this little plane will stay aloft''

Chuck- would you happen to know the AUW of that model?