Oregon Aircraft Design LLC

(503) 876-8980

Since 1997


“I have used 7 Hirth engines ranging from 40 to 100 HP...”

"I have used 7 Hirth engines ranging from 40 to 100 HP over the last 14 years. I have had no major issues and have had the prompt and informative service that has made life allot easier with all my projects. I have found that with proper care and maintenance, Hirth engines are high quality 2 stroke engines that are clean looking and provide good performance on all different types of aircraft and ultralights. I've had a good relationship with both Matt Dandar the US distributor at RPE and recently with Bill Larson, from Oregon and would recommend the Hirth product and services to all. (F-30-100hp PPC -2706 - 65hp PPC -3203FI 65Hp PPC - 3202-55Hp PPC - 2702-40Hp PPC 3203-65Hp X-Air Std - 3203-65Hp Seaplane PPC)."
—Steve Raklovits, Michigan

“This engine is a joy to use...”

"Re: Hirth F-23. When I first built my Fisher 202 I started out with a 40 hp Kawasaki engine that lasted 10 hours. I replaced it with a Rotax that lasted 99 hours. Both of these engines had the muffler outside the engine compartment. I wanted an engine and muffler that I could enclose inside the cowling. I did look around at other engines but the measurements did not fit my requirements for the 40 hp limit I wanted. I then looked at a Hirth F-23 which came nearest to my requirements. The height of the engine allowed for room for a muffler under the engine and inside the cowling. The width of the engine itself fit inside the cowling except the spark plugs. To accommodate the spark plugs I cut holes in the cowling, which did not detract from the appearance and allowed me to change the spark plugs without removing the cowling. The F-23 engine has a compression relief system for easy starting. I installed a new battery when I put in the Hirth engine and I credit the compression relief system with the fact that I am still using this same battery. I do not touch the carburetor jets winter or summer. They give me the same readings year round. EGT and CHT read the same winter and summer with no adjustment. I added a muffler wrap type heater to give me cockpit heat through the fire wall, which works great! Even the joy stick is warm in winter and my feet are comfortable. It's fun flying over the ice. I have 700 plus hours on the engine as of this writing. It has never been in the shop except for an update on the electrical system which Hirth provided for free. I am still running on the original pistons, rings, bearings, seals cylinders and crankshaft. Other than regular maintenance like replacing the spark plugs and drive belt there has been no mechanical work required. I still receive good compression, and cannot detect any change in power loss. I average about 100 hours a year. This engine is a joy to use, and as you can see, has given me many hours of trouble-free pleasure. To anyone interested in the above applications, I would highly recommend the F-23 engine."
—Robert Harwig, Wisconsin

“I am very impressed...”

"Hello Mr. Larson, I have finally finished the installation and testing phase of the used Hirth 3003 and new Kiev #263 you sold me for my CGS Hawk Arrow 2 and I am very impressed with it. So impressed that I'd like to share with you and any prospective buyers out there thinking of either buying a new, used or overhauled engine that they could feel confident they found an honest person and competent mechanic. I only say this because of my few dealings with Mr. Larson and that I sent him my carbureted 3203 over a year and a half ago shortly after I acquired my plane and had him do a complete teardown, de carbon, inspection and replacement of anything that needed it. Mainly due to the known hard/extreme environment and operations the engine saw before I purchased it, so I was a little worried about the internal bearings etc, but he checked it out and found it to be in good order. I had him replace a few extra things at my request just for peace of mind anyway. Since then I have put 165 hours on it after i got it back (260 total) and it runs and performs perfectly.  But I was looking for more climb performance since some of the mountains and valleys where I fly often range from sea level to upwards of 4,000 feet within three horizontal miles. I really like the 3203 a lot, it's been an absolutely solid engine. But I always/usually fly with a passenger and close to gross weight limits most of the time so I just got tired of having to run the poor 3203 in the 6000- 6200 range all the time to get over the mountains. So I swapped the 3203 for the 3003 fuel injected and it remedied any and all climb issues as well as the higher cruising rpm with the smaller 3203. So here are the numbers. Climb at 1000 LBS gross is now a solid 1,100 fpm vs 450 before. Solo climb is a solid 1600 fpm with 10 gal fuel vs 850 fpm before. Cruise went from 5800 to 4600 at gross and the speed stayed close to the same (68 mph). Solo cruise as low as 4000 vs 5200 (58 MPH) but the most impressive thing so far is the fuel burn. 3.5 gph solo with 3203 vs 3.7 gph with 3003. And at gross (2 people on board) 5 gph 3203 vs 5 gph with the 3003! Level wide open speed of 75 mph with 3203 vs 100 mph plus with the 3003. Of course you could make the 3003 drink more but it purrs so smoothly and quietly down in the low 4,000's you really don't need to run any more. Thanks again Bill, and if I ever need anymore climb I'd be going with that 71" Kiev like you recommended but I thought I wouldn't of had the clearance for it. In hindsight I did, but the 67.3" #263 is working smoothly so far. Thanks again."

“I endorse his quality workmanship...”

"June 6, 2004, To Whom It May Concern, My name is Scott Resnick, I am the shop foreman and manager of Northwest Aircraft Maintenance, Inc. of Hillsboro, Oregon. For five years I had the pleasure of having Bill Larson, now president of Oregon Aircraft Design, work as the lead mechanic on more than 80 annual inspections. Bill consistently showed a level of safety and trustworthy maintenance which gave me the confidence to sign off his work day after day. Bill’s innovative designs lead him to start his own business which has been able to help the aviation community with safe and effective products. I often install his products to protect the long term investments which my clients have made in their aircraft. As a pilot I have flown with confidence behind engines which Bill has maintained, some for more than a decade. We have never had a maintenance related incident, or accident in the fleet of more than 100 aircraft on which Bill has performed maintenance. Without reservation I endorse his quality workmanship and high level of safety. Sincerely,"
—Scott Resnick

“All the way to Oregon...”

"Hi Bill, I just wanted to let you know I finally flew my gyro the other day for the first time and the engine ran perfect. When I told my flying friends I was sending my Rotax 503 all the way to Oregon to be rebuilt by Bill Larson they thought I was nuts. But now they see how nice the engine looks with the custom paint and how well it runs. No one is laughing except me enjoying the air time. Thanks again, Bill. Fair price and great job!!!"
—Jamie Cleary

“Very good price...”

"My 582 was running fine with over 6 years without an overhaul. After consulting with Bill I discovered that Rotax recommends replacing all the engine seals at 3 years or 5 years maximum. Bill overhauled my engine, including performing all the precision measurements, cylinder hone and replacing all the seals and gaskets. He also gave me a free log book with a professional A&P entry and a written warranty. The job was completed in a timely manner, very good price and the engine runs great. I would highly recommend Oregon Aircraft Design to anyone."
—Robert Case

“I would highly recommend Bill...”

"At first I thought, What am I doing, sending my 582 to someone I’ve never met? Bill requested that I ship my engine to him so he could inspect it and tell me what it was worth. I thought Yeah, right, but for some reason, I decided to take the chance. Bill notified me by E-mail as soon as the box arrived and quickly thereafter e-mailed me with a detailed report of his findings and the amount he would offer for it. I was pleasantly surprised and accepted the offer since it was fair to both of us. Bills check arrived within one week. Based upon his honesty and integrity, I would highly recommend Bill Larson and OAD. Sincerely,"
—Ed Cully, Arizona

“My 503 is running great!...”

"William, My 503 is running great! I installed it on my t-2 back in september after I finished fabricating the fan-shroud and the rest on the support bracing. It fired up with no problems at all, once the carberators were set-up, adjusted and trimmed to run together. My set-up is running an E drive 3:1 65" B blade which was producing 350 Lbs of thrust static measured at Don Stutts place back in Dec. You have one satisfied customer here and will gladly reccommend you!"
—Glenn Duhon

“It always impressed me...”

"The Hirth 110 hp Fuel injected F-30ES is a great engine. I used mine in an experimental helicopter for 85 flight hours. There's quite a bit of shock cooling involved in practicing autorotations, and that's the great thing about a Hirth -- it's resistant to the effects of shock cooling. It always impressed me with how reliable it was, which was magnified by the fact that the rest of the helicopter was rather nerve-racking. These engines are very tolerant of heat, and aren't as loud as you'd expect. I'm parting out the helicopter and would use this engine in some other project if I had one."
—Jacen Keller

“That run up filter is very handy...”

"I bought one of your run up filters about two years ago. I'm an A&P/IA working on about 15 single engine Cessnas including 4 182's. That run up filter is very handy to use to ensure clean, filtered air without having to install the lower cowl, especially while making adjustments like setting the idle mixture. Thanks again for coming up with the filter and offering it to other mechanics."
—Jon Farmer

“You have yourself another happy customer...”

"Engine has just arrrived, many thanks Bill very pleased with it was very well packed and exactly as advertised, I appreciate your patience and cooperation during our emailing back and forth..you have yourself another happy customer... cheers."
—Mike Kindon - New Zealand