Date: Mon, 3 Apr 1995 19:09:30 -0400 From: CCady@aol.com Subject: Re: Mail List request Hi Marc, The gear is the same as the Berkut uses because they bought the design from Shirl Dickey who I understand provides the carbon fiber gear legs. I got my gear legs from Shirl several years ago and they are fiberglass. They pivot points inside on my E-Racer are two 1/4" plywood stringers that are 18" apart and run from the back of the front seat to the firewall. This also is the bed mount for the V8 the he uses. I am using a Lycoming. The gear pivots mount to the stringer just ahead of the center section spar and go out thru the sides thru slots that are beefed up at the opening in the sides. There is a beefy overcenter linkage that goes from the gear leag near the sides and up to a real beefy fiberglass mount just under the longeron and attached to the side. The overcenter lingage is hinged in the middle and a mount for the hydraulic cylinder extends off the top half backward. The retract hydraulic cylinder attaches to this at the top and the lower longeron at the bottom and sits just ahead of the center section spar with the gear leg ahead of it. It's pretty strong looking. I have ordered and recieved a set of gear legs that are sold by Infinity Aerospace that are much better in design and can be used on the Long-Ez and Cozy MK-IV. They are a oleo strut that compresses prior to retraction and mounts to the end of the centersection spar. The quality is excellent and I have seen it installed and operating in a Long-Ez to which it was retrofitted. Nat Puffer does not endorse the use of this gear (see latest newsletter) but I understand there are several builders who plan to use it. I have seen a video of the drop test they did on the Long-Ez where the fuel tanks were filled with water (heavier) and the thing hoised up 12" or so and the rope cut. The oleos absorbed the shock pretty good with no damage to the pane or gear. It's a really nice design that gives you a wide track. It's not cheap but it gives you 18-25 mph. But it will reduce the fuel capacity some unless you make the tanks larger by reducing the strake baggage or something. Infinity advertises in the back of Sport Aviation all the time. They are finally making deliveries and I wanted to make sure I had a set for my next canard probably a Cozy MK-IV. Cliff Date: Tue, 4 Apr 1995 16:34:25 -0400 From: CCady@aol.com Subject: Cozy retracts, Nat says no! Question, to consider retracts or not? I noticed that in the latest Cozy newsletter Nat discourages the idea of retracts for the MK-IV. From a designers point of view I'm sure that encouraging an untested modification is not feasable. Many of his warnings about the extra work and forgetting to lower the gear are true, lets face it. You've all heard the old line about the two kinds of pilots "Those who have and those who will, forget to lower it" I like the idea of retracts mainly because I want the 15-20 mph increase in cruise speed. But on the other hand, I know that the speed doesn't come cheaply! The extra work installing hydraulic lines alone is significant since you have to install mounting points to support them at intervals to prevent vibration and so forth. Then you have the wiring involved with the hydraulic pump, pressure sensors, gear positions microswitches, indicator lights and so on. On my Long-Ez, I remember I was pleased to get 5 mph by adding wheel pants and remember thinking, that it would be much better if I had retracts? Retracts are now available on many canard homebuilts such as the E-Racer, Berkut (uses the E-Racer gear) and Velocity. Retrofit gear is available for the Long-Ez & Cozy MK-IV by using the Infinity retractable gear which is advertised in the classified section of Sport Aviation magazine. I am just finishing up my E-Racer project and can comment on it's retract gear. First, the parts for this gear aren't cheap or really easy to install either. I can't quote current prices for the parts, but by the time you buy the carbon fiber legs and all thats needed you are into several thousand dollars. It's a pretty compact installation but it takes about a foot from inside the fuselage just ahead of the spar. Also it requires openings in the fuselage sides for the gear legs to travel up and down in. Since the wheels retract into the outer ends of the strakes where they are slightly thinner it can be a tight fit, you may have to have bumps in the skin for clearance or mount the wheel canted inward at the top to make it fit. I have bumps on the bottom gear doors to clear the brake calipers and the wheels are canted inward to eliminate the need for any bumps in the top skin. I saw the Infinity gear last year at Sun-N-Fun installed and flying in a Long-Ez. It was retrofit to the Long-Ez and documented on video which showed a drop test to confirm the installation's strength. If you haven't seen the Infinity gear it is a somewhat conventional looking oleo gear that mounts to the end of the centersection spar, which is beefed up at the outer ends on the inside with extra layups. It retracts inward into moulded wheel wells in the strake. The gear pivots on a substantial shaft which goes thru an aluminum mounting plate which is bolted to the forward side of the spar and the other end of the shaft pivots off a mount that bolts to the exisiting wing attach bolts on the back side of the spar. In order to allow the gear to be able to retract into the space in the strakes, the gear legs shorten themselves prior to being retracted into the wheel wells. I was very impressed with the quality of the parts and decided to order a set to make sure that I had them for my next project. I was concerned that the small company might have limited production and I would no longer be able to purchase a set. I recently received my Infinity retract gear and my reaction is still very positive. They are made from precision machined parts and look very strong. They are not cheap at $4200 but you get a pair of precision machined gear legs that are ready for installation complete with retract cylinders installed. I really think this gear would be much easier to install than the E-Racer type gear. You also get moulded fiberglass wheel wells, hydraulic pump, valves and instructions and numerous other parts that you need. The installation instructions are somewhat lacking, being mostly a collection of schematics and drawings with little step by step instructions. These are mostly concerned with the hydraulic and electrical part of the installation. There is a video available which I haven't seen which shows installation details. I'm not endorsing the idea of using retracts because I know that the installation adds many hours of extra work and it costs alot more. The payoff is having that extra 15-20 mph cruise speed. At least you have the option if you have to have it. What do you think? From: Marc J. Zeitlin Subject: Cozy retracts, Nat says no! Date: Tue, 4 Apr 95 17:14:05 EDT Cliff Cady writes: {much text about retracts deleted} >I'm not endorsing the idea of using retracts because I know that the >installation adds many hours of extra work and it costs alot more. The payoff >is having that extra 15-20 mph cruise speed. At least you have the option if >you have to have it. What do you think? Well, having a total of ~40 hours in gliders (2-33's and 1-26's) and ~70 hours in 150's and 172's, never having flown the Q2 I built, and having finite amounts of money, I'm leaning toward erring on the side of least # of modifications to the original design (as much as I want ALL the electrically operated crap, as well as retracts). I figure that if I can get this puppy built and in the air, and it actually flies twice as fast as anything I've flown before, I'll worry about the retrofittable stuff later, even if it will cost more and be harder than if I did it up front. Cliff, you're WELCOME to do the experimentation for us :-). None of this is to imply that I wouldn't LOVE to have the retracts, etc. :-). -- Marc J. Zeitlin E-Mail: marcz@an.hp.com Date: Tue, 4 Apr 95 17:14:05 EDT Subject: Cozy retracts, Nat says no! Cliff Cady writes: {much text about retracts deleted} >I'm not endorsing the idea of using retracts because I know that the >installation adds many hours of extra work and it costs alot more. The payoff >is having that extra 15-20 mph cruise speed. At least you have the option if >you have to have it. What do you think? Well, having a total of ~40 hours in gliders (2-33's and 1-26's) and ~70 hours in 150's and 172's, never having flown the Q2 I built, and having finite amounts of money, I'm leaning toward erring on the side of least # of modifications to the original design (as much as I want ALL the electrically operated crap, as well as retracts). I figure that if I can get this puppy built and in the air, and it actually flies twice as fast as anything I've flown before, I'll worry about the retrofittable stuff later, even if it will cost more and be harder than if I did it up front. Cliff, you're WELCOME to do the experimentation for us :-). None of this is to imply that I wouldn't LOVE to have the retracts, etc. :-). -- Marc J. Zeitlin E-Mail: marcz@an.hp.com Date: Tue, 4 Apr 1995 21:36:34 -0400 From: RonKidd@aol.com Subject: Re: Cozy retracts, Nat says no! As a Cozy Pilot (450 hrs on my bird) I can say that I am glad I don't have a full retractable gear. The damage I incurred on my gear up landing (yes it can happen to you too!) was repaired in a weekend and I was back in the air by Monday. It would have been an obvious disaster to have slid down that long runway on the belly! Besides, how fast do we need to go? I cruise at 190 mph. I thought we flew because we like to fly! Whats the big hurry? Ron Kidd N417CZ Date: Tue, 4 Apr 1995 21:57:21 -0400 From: CCady@aol.com Subject: Re: Cozy retracts, Nat says no! Hi Marc, I think you have a good point about keeping it simple. But I think if you had to have retracts the Infinity approach where you basically install a complete assembly is the way to go. The E-Racer way is where you have to fabricate your own parts and fiberglass hard points and do alot more work to make it fit. I'll bet I spent several hundred hours on various things related to the retract system. And you would not believe how expensive all the hydraulic fittings you will use cost! I just got my Sport Aviation, love that Glastar highwing! Can't finish what I've got and drooling over another :-) Date: Wed, 5 Apr 1995 07:57:58 -0400 From: SidLloyd@aol.com Subject: Re: Cozy retracts, Nat says no! <<>> >I'm not endorsing the idea of using retracts because I know that the >installation adds many hours of extra work and it costs alot more. The payoff >is having that extra 15-20 mph cruise speed. At least you have the option if >you have to have it. What do you think? I considered this early on and regretfully dropped the idea due to the following: pros: looks cool more speed (10-20 mph) cons: less range (eliminates 5-7 gallons of capacity) more complexity (more to go wrong) more expensive (about 4-5K) more weight (= less payload, reportedly about 10-20 pounds) significantly higher danger in a gear up landing (nose only=scrape, main up=prop strike, possible catastrophic tumble) major re-design (Nat says main spar isn't stressed for Infinity gear) So, I finally decided the cons outweighed the pros. But it would sure look cool! Sid Lloyd Date: Thu, 06 Apr 95 13:20:28 est From: "Phillip Johnson" Subject: Re: Cozy retracts, Nat says no! I read the article the Nat wrote in his news letter and the few others that have preceded that in previous news letters and I conclude that Nat suffers from the famous NIH syndrome (Not Invented Here). The arguments are weak and inaccurate. I have the same Infinity gear that Cady has (sorry I don't know your first name) and it has been adequately described in your E-Mail message but the overall concept does not seem to be addressed objectively. The question that should be asked is "DOES THE RETRACTABLE GEAR MAKE THE COZY A BETTER AEROPLANE?" The issues of gear up landings are real but is not Cozy specific, nor is it dangerous and clearly there many designs around using retracts suggesting therefore that it is not overtaxing to the pilot, i.e. It's nothing new. The cost is higher than fixed gear typically $3500 if you deduct the cost of pants and the cost of the main gear hoop. So what do we need to do to decide whether RG gives a better aeroplane? First of all we need to define a baseline form which to work, and this should be the stock Nat Puffer Cozy Mk IV. This aircraft weighs in at 1050 lbsempty and has a 2050 lbs gross weight i.e. a useful load of 1000 lbs. This baseline carries a maximum of 50 US gallons (300 lbs) and has a max speed of 216 mph according to the POH. If we now add the infinity retracts there is a weight increase of approximately 35 lbs and a loss in fuel, within the strakes, of 8 to 10 gallons. The increase in weight, at first sight, causes a reduction in useful load, but this is not the case since the same aircraft equipped with retracts consumes 80% of the fuel, or 60 lbs less so the payload has increased by 25 lbs with no loss in range provided the same speed is maintained for both aircraft designs. (This 80% value is measured data from Bill Threeringer's Long-eze). We therefore have a BETTER AEROPLANE. The loss in fuel does not impact the range. For less than maximum range journeys the speed advantages are obvious. The above scenario is not total. The old landing gear box may be used as a fuel sump which has a volume of approximately 1 cubic foot or nearly 8 gallons which is almost all of the fuel you lost when you put the gear in, so when you fly an equivalent payload in both the fixed gear and the RG with sump tank (i.e. using the extra 25 lbs of fuel) you now have more range, or given that you are not payload limited your range has increased almost 20%, or you can go the same distance faster. YOU HAVE A BETTER AEROPLANE. Data obtained from Bill's 160 mph Long-eze indicated a 10.5% increase in speed i.e. a drag reduction of 26%. This same drag reduction applied to a MKIV yields in an increase in speed from 216 mph to 239 mph i.e. some 23 mph increase. My guess that the the gear drag is less significant on the Cozy than on the Long-eze so this figure is optimistic but a figure of 20 mph is probably real. I will be happy with 15 mph. YOU HAVE A BETTER AEROPLANE. Nat describes the gear as moving the location of the wheels back thus affecting take off performance. This is incorrect. The wheels lie at FS 110 the same as the standard configuration. Now we should address the subjective issues. Imagine you have an engine failure and there are no roads or runways within range. In water landings have proved to be fatal with two exception since the main gear digs into the water causing the nose to dive into the water. It is likely, but not proven, that on water landing with the main gear retracted and possibly some extension of the node gear, that the Cozy will skip on the water, or snow for that matter, thus making for a safer landing. YOU HAVE A BETTER AEROPLANE. The issues of strength in the main spar are a Red Herring, The spar suffers enormous torque caused by the sweep back of the main wing. The landing torque, caused by aggressive breaking, impose significantly lower loads than those in flight. The cut out in the lower skin has been replicated on the Bearkut, Velocity and the E-Racer with no extra structure in the spar to accommodate the airload torque caused by the sweep back so Nat argument for flutter is without foundation. For good measure I will be including a shear web on the front face of the spar instead of the 2 two plies of BID simply because I can do it whith no extra work, but it is not necessary. On speaking with Infinity Aerospace on this matter I found out that they employed an independent company to calculate the required lay-ups necessary to achieve the required strength of the spar for his application. I wonder if Nat has ever analysed the structure? I went through this objective analysis before I bought the unit and I could find no reason for not going ahead. It's not for everyone but if you don't mind the extra risk of a gear up landing, you have $3500, and you are happy to do the extra maintenance associated with a retractable set-up and you want A BETTER AEROPLANE then go with it. Phillip Johnson RG Date: Tue, 7 Nov 1995 08:42:32 -0500 From: Phillip.Johnson@Lockheed.on.ca (Phillip Johnson) >>There is nothing wrong with the gear but the modification is necessary. > Did any tell that to the guy who crashed ;-). I spoke with JD Newman on Sunday and he told me that he (the builder) had been told of the roll pin modification. I was told months ago and I know many others were also told. Sometimes people don't listen and think the problem will go away. > Stories like this really make a fixed gear Cozy sound good. If we believed every story at face value we would not be building canard aircraft. The conventional aircraft owner/builder could apply the same argument to the stall characteristics of the canard design, but we know better. We know that so long as the design is carried out correctly and the weight and balance criteria is obeyed, life is good. Retracts are not for everyone, they give a performance gain at some cost, and if they are not installed correctly they are a liability. Phillip Johnson Date: Tue, 7 Nov 1995 08:52:32 -0500 From: Phillip.Johnson@Lockheed.on.ca (Phillip Johnson) Subject: Re: 2nd AeroCanard flys!! > Just a quick note. Talked to Nat during the last EAA meeting. He > said that the Infinity Gear (used in the aerocad) will no longer be > covered by Avemco Insurance. Has anyone else heard this? I'm not > going to use the gear myself but those who are entertaining the > idea may want to know. Good old Nat he is so predictable. I spoke with JD Newman over the weekend and he told me of the Avemco issue. He said that Avemco did initially express concern, but after he had seen the equipment and had seen that an Infinity Aerospace roll pin AD had been issued Avemco revoked its original statement. Phillip Johnson (1.38.193.5/16.2) id AA02026; Wed, 15 Nov 1995 19:02:13 -0500 From: "Volk, Ray" Subject: Retractable Gear Date: Wed, 15 Nov 95 16:50:00 PST Encoding: 14 TEXT Scott I have not completed chapter 9 so I can't offer you any advice on installing someone else's fixed gear. I would however, be interested to know if your friend is on the network and if so if I could get his address, as I too am considering retractable gear. I would be interested in communicating with anyone who is considering or has decided to go with RG. I have videos on the Infinity gear as well as the one advertised in the Central States News letter. If not the same it is very similar to the gear used on the Velocity. Ray Volk rvolk@space.honeywell.com