|Sep 26, 2011, 10:22 AM|
Spirit of Glenn Curtiss
For the past few Septembers, I have attended the Glenn Curtiss Annual Seaplane Homecoming. This event takes place at Hammondsport which is located at the southern tip of Beautiful Lake Keuka. This is a very low key event which pays homage to arguably the most innovative Aviation Pioneer. If you are within driving distance I would recommend attending this event -capped off by a tour of the Curtiss Museum.
Often, a Vintage Curtiss aircraft is flown as an event attraction. Last year a 1912 Navy Seaplane was flown. But this year was very special to me. I learned that Dale Kramer was going to fly his Electric Powered Lazair. I have never seen a 100% scale electric fly (in person) and it is poignant that this flight would take place at exact location that the Curtiss achieved the World’s first successful Seaplane flight, over 100 years ago.
I was doubly interested since I was an “acquaintance” of Dale’s –before his Lazair days. I actually knew Dale’s Dad better, since he graciously invited us to use his shop to create some parts for our Homebuilt Aircraft. We would see Dale working on one of many designs he built and tested before the birth of the Lazair. Dale was still in his “teens” and I think I saw him working on a Plank (no sweepback) type of “Flying Wing” that he intended to fly to Oshkosh.
In any case (IMHO) the Lazair was “light years” ahead of that era of “Ultralights” which were mostly single surfaced sailcloth winged designs that were braced by a zillion wires. The Lazair was very successful and received many accolades and awards. I truly believe that the design is still one of the most efficient and innovative aircraft when compared to current “103” designs. For one reason or another, I totally lost track of Dale and his whereabouts for over 30 years.
When the E-Lazair flew past the crowd at Hammondsport, I found the experience almost surreal. I had envisioned that one day I would witness this flight, ever since I flew my first “Kludged” RC electric model over 40 years ago.(a converted 2 meter polyhedral sailplane-using a ferrite motor that matched my 6*4 prop)
To say that the Lazair flew very well would be an understatement. Dale flew several “close-in” passes at a very low throttle setting (3100 rpm-I think). At this power setting...the Lazair was “on step” i.e. Not flying in an elevated alpha ( AOA) or struggling to fly at that power setting. It was sufficiently in the “groove” that Dale made several fairly tight -low altitude -180 degree turns in order to stay in front of the crowd. He would not do this-if the aircraft was even close to a tip stall. The flight was culminated by a gentle landing...very near the ramp.
The Lazar definitely stole the show. A large crowd gathered and had endless questions-which Dale fielded with class and patience.
We are fortunate that Dale has shared his development with us. He is modest when talking of his experience and abilities. I knew that Dale was a great designer and a craftsman...but I had no clue he had such a depth of not only motors but in electronic design. If you closely look at the photos he has posted-you will see superb CNC machining (throttle quadrants) and very professional custom PC boards that I believe he created using “layout software... Innovation and craftsmanship are evident in each detail.
There are many parallels relating to Curtiss and Kramer (If you read a Bio of Curtiss).
So I don’t think is too much a flight of fantasy for me to say that Dale’s demonstration at Hammondsport evoked the Spirit of Glenn Curtiss.
I do have a background that may help me create posts that may be of interest to those whom follow this thread. I would like to move the conversation forward since (IMHO) we have not scratched the surface. To this end, I will post when I get some time (soon). Retirement is a full time job!
|Sep 28, 2011, 12:48 AM|
Glen Curtiss / Dale Kramer
Though I've admired the Lazair since it flew gracefully onto the ultralight scene three decades ago I only met Dale this spring. I happened to be visiting near Hammondsport and a friend emailed me a link to this thread. As if by magic it was the day of the Electric Lazair's maiden flight. I called, talked to Carman and met the maestro the next day. Thanks again Carman and Dale for your warm hospitality.
Glen Curtiss / Dale Kramer, soul brothers of aviation innovation. Separated only by time.
I just finished reading "Glen Curtiss, Pioneer of Flight". Pick it up at the library. You will love it.
|Oct 05, 2011, 11:02 PM|
Update -- water flying is finished for the year
Sorry for slow response.
I will reply to Brians thoughtful posts when I get a chance but I will be very busy for the next few weeks.
The electric Lazair has 50 hours of 'wheeled Lazair' equivalent (where 1 hr of float time is treated as 1.6 hr of wheeled time) flight time on it and has been flown by 14 people.
Rather than hibernating the electric Lazair here for the winter I have a friend in Uvalde Texas who has volunteered to hangar and fly the Lazair this winter.
This will keep adding hours onto the Zippy packs and confirm what life we should expect from them. It will also allow us to figure out a system that will isolate weak single cells in the packs which can be replaced to futher extend the life of the whole pack of 64 cells.
So, I am driving the Lazair to Texas tomorrow and flying back next Thursday. Then Carmen and I will jump right into our RV8 for a trip across the country so that I can show up at Scaled Composites in Mojave on the 26th to give a talk and have a tour.
Here are a few pics of the new Texas tires (no flat) and disc brakes I have installed on the plane.
So, I may not have much time to post for a few weeks yet.
|Oct 06, 2011, 02:59 AM|
Joined Jan 2004
First off all, guess like most of the RCgroups users here, I'm totally impressed by your work.
Flying electric is nothing special in these days, but take the cheapest possible route for make it available to as many people as possible, it is very impressive.
Here in Europe is impossible to find any ultra-light that cost much less then 100.000$ ... your Lazair can be sourced in US for around 4000$, and new one if I don't guess wrong, it was around 10.000$
I'm sure you can restart production with electric version and having a selling price in the 10.000$ range.
Do you know if there is any chance to source your Lazair in Europe?
But mainly, do you have any plan to start selling this Electric Lazair ? Maybe only in kit version ?
What about using the Turnigy motors, these cost less then the half then the one that you finally used ... is something that you are still considering ?
Thanks a lot in advance.
|Oct 07, 2011, 06:53 PM|
Joined May 2011
Fourteenth Pilot Report
I have been a Lazair enthusiast, builder and owner for the past 30 years. This last weekend I had the good fortune to fly Dale Kramer's amphibian Series 3 that he has chronicled the conversion to electric propulsion right here in this blog. Dale and Carmen made the offer to me to fly it at the conclusion of AirVenture at Oshkosh, Wisconsin this Summer (where they received an unprecedented two awards from the Experimental Aircraft Association). Schedules, and then a severe head and chest cold scuttled my plans to visit during the above mentioned Seaplane Homecoming Event in Hammondsport. Dale indicated that he needed to remove his Lazair from the lake by the end on September, so my wife and I high-tailed it there from our home in Virginia Friday morning. We arrived in New York as a humongous low pressure system proceeded to park itself over the state - and several surrounding ones.
It had been a couple years since I had the pleasure to visit the Kramers and I looked forward to catching up a bit on things and Dale's myriad projects. My wife hadn't seen Dale in 28 years and had never meet Carmen so she also had something to look forward to on our visit. I admit I felt some disappointment at the almost sure prospect of my flight getting washed out but it sure wouldn't have been the end of the world for me either.
It proceeded to rain Friday evening, Saturday (with white caps on the lake!), Saturday night, and Sunday morning. Oh boy did it ever rain Sunday morning. As lunch passed we went looking for rain gear to use while taking the plane down - and then the rain just stopped. We checked weather radar to discover the eye of the storm passing right over us! An hour and a half later I was in the air - the 14th. person to fly Dale's electric conversion.
I have flown virtually every model and variation of the Lazair over the years. Engines include the 99cc chainsaw motor (both direct propeller drive and my own prop-speed reduction versions), 185cc Rotax (with bi-blade and long blade props) and a couple different twin cylinder engines. Aircraft weights ranged from not much over 150 pounds to around 350. Dale's conversion, for reference, weighs around 400 pounds with the float gear installed! So you can imagine my anticipation in doing a comparison to my past experience flying these planes with their 2-stroke engines.
And the comparison IS quite interesting. Other than the "barking" sound at start-up while the sensorless Joby motor and the motor, controller try to communicate and play nice, the smoothness and linear throttle control is quite satisfying. Actually, the start-up ruckus of the electrics only lasts a second and is light years better - insignificant - compared to the normal, obnoxious 2-stroke engine start-up/cold idle/ warm up routine. I had watched Dale fly numerous times at AirVenture along with countless times on YouTube videos but I was still unprepared for the level of performance that I experienced. I truly didn't expect the short take-off, nice climb, and speedy cruise speeds of this plane fitted on the huge, heavy seaplane gear. All the while the smooth running Joby motors never sounded the least bit stressed, and motor temps seemed ridiculously low when you consider how small the motors appear. Within a few minutes I was totally comfortable with the electrics despite the winds aloft. The motors ran super smoothly and responded to throttle settings perfectly. Soon I was totally relaxed and running through a variety of maneuvers. Of special note to me was how strongly the motors pulled on take-off, and yet at high cruise speeds the motors never let the props unload; something that is very hard to produce when using 2-stroke engines with their narrow power bands. I think that is one reason this plane performs as well as it does with only these two small motors. A word to best describe the conversion may be synergy - this marriage of airframe and electric motors works very well. This thing I was flying was a very happy machine! I found myself content to just cruise the lake shore at 3000 rpm reminiscing of the flights I made 30 years ago in Canada floating along the lake shore by Dale's home there in what was then, I believed, a ground breaking Ultralight aircraft. Actually, I found myself rather overwhelming in an emotional way. Sometimes I forget what an impact the Lazair has had on my life.
Too soon the dual voltmeters indicated that the battery packs had sagged to 57 volts (at cruise power) - the point at which I had been directed to begin planning my landing. As much as I wished to continue this flight, even as I fought back the shakes from the cold that permeated my outfit, we swung a large descending turn out over the lake and back. When parallel to the shore near Dale's dock, and facing into the wind, I reduced power to 1200 rpm for the final decent. The heavy craft sank somewhat faster than I had anticipated and, running out of control authority at the last instant, we arrived with a solid splash. No damage - except to my pride! The twin motors, generally unappreciated for their merits by Ultralight pilots, proved to be brilliant when maneuvering this small seaplane on the rough water. The electrics, with their ability to shut down and then restart almost instantly, made taxiing about the lake childs play. Very Cool. Despite not trying in the least to maximize flight endurance, recharging the packs indicated 20% charge still remained. My flight had lasted 35 minutes.
This conversion of Dale's venerable Ultralight design stunned me by its level of refinement. While others have produced prototype after prototype, Dale has produced a sophisticated product level set-up the first time out. I should not have been surprised. The same mind conceived and designed both!
Bob Chapman (Chappy)
|Oct 16, 2011, 12:13 AM|
Joined May 2011
Quite interesting to read your posts and review your calculations. I don't know the actually rate of climb (ROC) of Dale's plane the day I flew it as Dale isn't big on flight instruments.* There was a good breeze coming down the lake the day I flew. That helped in getting off the water much faster than I had anticipated and made for a steeper climb angle. That messes with you when you're trying to figure ROC by instinct. But considering the way it flew for me, all I can say is that even with all the weight of the batteries (compared to the usual 5 gallons of gasoline) and the extra weight of the floats, I didn't feel like the plane was underpowered for a Lazair. Between the floats and batteries I would think it was almost 150 pounds heavier than a typical Series 3 Lazair would be, and then there's the additional drag from the floats. I probably weighed in around 225 pounds with heavy leather coat, old military helmet, gloves, wetsuit booties full of water, etc. but still somewhat less than Dale. If I had been able to fly the plane in a more typical configuration I'd have a better frame of reference - but I have to believe that the performance that way would be a blast! BTW, Dale has always been painfully honest in rating his aircraft's performance numbers. When he was selling kits for the plane I believe he was one of very few in the industry to publish actually, real world numbers. A few of his competitors inflated ROC by two times or more. Rotec with their Rally 2B was the most flagrant abuser in my opinion. I'm sure that hurt Dale's sales significantly over the years but he wouldn't bend to the industry norm.
The original Series one Lazair kit came with a pair of modified chainsaw engines. The engines were bandsawed off of the industrial saws at which point they weighed 5 and a half pounds each, or roughly the same as the Joby motors, but making less than half their power. The flywheels were modified so props could be fitted to them, and new housings made by him were used to fit the recoil starters onto the output shafts of the engines. Wooden props were used but before long fiber-reinforce nylon props replaced them. They were made in-house at Dale's Dad's plastic injection company, as were the wheels and various other small parts. IIRC, that set-up with the more efficient plastic props made something like 37 pounds static thrust per engine. The engines were somewhat prop-limited so only made about 4.5 HP (each). Re-drives were the big deal of the day so I decided to try my hand at it. One reason was that a friend had covert access to the propeller design program that Paul MacCready developed for the Gossamer Condor project! That enabled me to design (on an Apple IIE clone with 64 K Ram!) a very efficient wood prop. With tuned straight pipe exhausts fitted, I was able to wind the little engines up to rated output (5.5 HP) and I recorded 65 pounds static thrust each thanks in part to the much longer, slower turning props used. My first short flight resulted in severe ringing in my ears for a couple days so a pair of lawn mower mufflers were fitted to each engine. That, and a bit more realistic carb tuning (richer to help lowered astronomical cylinder head temps), dropped static thrust by about 10 pounds each. I think the most fun is taking the plane to fly-ins and when asked about the engines, I respond that they make 11 HP - COMBINED - and watch their reaction. Wish I had videos of some of them! I don't want to totally hijack this treat from the RC guys so if you're interested, pictures of the re-drives can be found here: http://groups.yahoo.com/group/lazair...59466/pic/list
Looking forward to Dale posting again!
* Almost 30 years ago Dale offered up his proto-type 2 seat Lazair trainer for me to fly and take my wife up for her first Lazair, and Ultralight, flight. I was probably 30 feet in the air before I noticed that there was no airspeed indicator mounted on the plane and responded with a few choice words. Soon, though, I was marveling at how an airplane like the Lazair could "talk to you" when you weren't just flying the numbers as I was taught in flight training.
|Oct 16, 2011, 07:59 PM|
Joined May 2011
A picture I took of Dale machining the disk brake mounting hubs for the thorn proof tires/wheels shown in a previous post by him. The original wheels used pneumatic wheel barrow tires and tubes and Dale felt they wouldn't hold up during testing this winter in Texas. Dale converted this old CNC mill to run off of a small netbook style computer running a commercially available software program. I helped (by trying to stay out of his way) while waiting for the rains to stop for my flight.
|Oct 31, 2011, 05:39 PM|
Joined Feb 2006
Large format Kokam batteries
I've read through the entire thread today and am very impressed and happy to find so many knowledgeable people in one virtual place, especially Dale to whom we all owe a debt of gratitude for his untiring work.
I am now attempting to convert an existing ultralight to electric also. I would however like to use large format li-poly cells and a full BMS. I converted my car to electric and used that approach with 31Ah Kokam li-polys in a 74V series connection and a full BMS. Unfortunately now I can't seem to find a source for large format li-poly batteries in the US. I've tried contacting Kokam directly but they will not respond. I know Electravia (France) and Flytec (Germany) both have Kokam packs for sale but the Euro exchange rate kills the price point.
Anyone out there know a source for Kokam large format cells in the US?
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