Cascade Aircraft Conversions

"It's All About Air!"


-Tom Miller- Ingalls, Kansas

" I love my Cascade Walter Turbine!"


- Ken Kane/ Ken Kane Aerial Spray- Manitoba, Canada

"I have been extremely satisfied with the Cascade Walter Turbine Conversions and will convert 4 more AT 401 aircraft this year!"


- Ron Drosselmeyer - Air Sprayers, Inc. - Two Buttes, Colorado



"Prior to installation I tested my AT402 ( -34 ) with an manometer and it registered a -5 ( showing it was short of air). After installing the Cascade Aircraft Conversions Pressure Cowl and testing with the manometer, it registered a + 10 ( a 15 inch difference in air available to the engine)! Throughout the season I never had to worry about overtemping the engine and never had a redline problem at any time."


- Dan Schellenberg - Air Dusters, Inc. - Roggen, CO

“It does what they say it will do!”


"The Cascade Aircraft Conversion Pressure Cowl is one of the best modifications I have put on my airplane! On an eighty degree day the engine performs like it was a 60 degree day."



-Krech Dakota-Airspray-South Dakota


"If you have any non believers just tell them to give me a call! You have really hit a home run on this one. So whatever you're doing, just keep doing it. The Cascade Pressure Cowl does everything and more than you said it would. The NG and the ITT are a non-issue now and I'm running an HONEST 50 to 60 degrees cooler! It's the first time in five years that I haven't temped-out and it's been kind of fun to just watch the temp. guage. We're also saving on the engine and reduced the NG by 4% and reduced the fuel consumption by 4 gallons an hour and that in itself will pay for the unit. There is less overall maintenance and th K & N air filter works exceptionally well. Now I have flown 536 hours with the Cascade Pressure Cowl and cleaned the air filter once, at about 250 hours. I was thinking about putting a PT-6 -34 on, but I don't know why I would need to change now."


Operator Reports:


David Travers- From Down Under

Pilot for Ken Kane Aerial Spray


There is no question the AT401 is a great aeroplane to fly....empty. However, put a load on behind that radial and, although it is still a good aeroplane, it's performance changes dramatically. It's ability to climb and turn decreased exponentially with the size of the load so on a hot day: it's a balancing act. That has now changed for me with the Cascade Conversion of a AT401B to the Walter turbine engine.

I currently have about 300 hours on type and find the over-powered nature of this installation gives incredible response by the aircraft in any flight configuration or attitude. Heavy or light, hot or cold, it turns as easily on the first run as the last, meaning I have full control of the aircraft and the flexibility todo the job properly. No more marginal let downs and pull ups leaving me to concentrate ona safer and better quality result.

On short, unprepared strips, I can use as much or as little power as necessary to give the best takeoff, resulting in les stress on airframe and pilot. With a lighter aircraft and more power I can spray out the first 100 gallons just as quick as the last. Downloading is about the last thing to consider meaning this is a true 400 gallon machine that is a delight to work.


In an industry with too many underpowered hoppers and overloaded wings, the correct combination of wing, hopper and engine size made the Cascade AT401 Walter the most enjoyable, most productive and the safest ag aircraft I have flown.


Ken Kane-Aerial Spray-operates a fleet of 13 Air Tractors.

For many years I have questioned the benefits of changing form radial engine to turbine, but held back because of cost and the uncertainty of its suitability to my operation.

In 2003, I decided to convert an AT401B to the Cascade Walter M601 Conversion. This decision would enable me to make a direct comparison to a radial engine, at less cost than the purchase of an AT402. The size of the AT401 is also better suited to my specific operation than a larger aircraft.

At the end of its first full season of operation I am pleased to make the following favorable comparisons between the Radial and the Cascade Walter Conversion.


Reliability- The Walter engine is maintenance free. No downtime during busy periods unlike the radial engines.

Horsepower- The 750SHP Walter engine allowed us to work safely from short runways fully loaded.

Size- The size of this aircraft is ideally suited to my operation.

Productivity- The extra power allows us to fly with a full 400 gal. load, compared to a 320 gal. load in a radial. This is an immediate 20% increase on productivity. In this first year of operation, we have found that with the extra speed and performance of the engine, productivity has been as much as 50% greater than the radial engine.

Fuel Consumption- We calculate a reduction in fuel costs of $0.30 per acre.


In conclusion, I have been extremely satisfied with the Cascade Walter Turbine Conversion, and will convert 4 more AT401 aircraft this winter.


The cost of the Walter engine, whilst involving a greater initial outlay, works out to be approximately the same as the radial, as it is a 3000-hour engine compared to 1000 hours on a radial. By taking advantage of the warranty program I calculate the engine costs to be the same, but with far greater reliability and performance.


Ken Kane, President

Ken Kane Aerial Spray (1988) Ltd.



Okay, here are the ingredients...             A 90 degree day

                                                            8,000ft density altitude

                                                            A pointy nose spray plane

                                                            A bank account that can't spare a $150,000 expense


          In our case it's an AT 402-A in eastern Colorado ( currently experiencing the worst drought in recorded history!).  My thoughts were this: the result of this recipe would be one PT-6 well done. No matter how you season it, slice it, bless it... you're going to have a big 'ole gut ache.  That was my worst fear, just like everyone else's at that dreaded hot section time.  We were warned... don't buy an 11AG, you won't be happy; spend the extra money for a -34.  Well "they" were probably right, except we couldn't afford it.

I would’ve done just that, maybe have bought two if there would have been a cash discount…ya right.


   I don’t mind admitting I was more than a little disappointed with the limited performance when the temps got high. My eyes were glued to the ITT all the time. I was close to trading my 11AG in for a –34 when I went to the NAAA convention in Vegas to look at Doran Rogers’ ( AKA Cascade Aircraft Conversions) pressure cowl. I spend nearly all my exhibit hall time looking and thinking and talking to Doran about the air scoop.  If you saw it I’m sure you’d agree it’s a beautiful piece or workmanship.  Doran told me what kind of temperature reduction and increased horsepower I could expect as a result of not being temperature limited. It made good “cents” to me. I placed my order at the convention fearing that if I waited it would months before they could fit me in.


   Upon returning home I called my brother Scott who had just purchased an AT402-A the previous month and convinced him to place an order with Doran also, so without even seeing one he also signed up.  The biggest obstacle ahead was getting the airplanes to Washington, flying VFR in the Rocky Mountains was something I wasn’t looking forward to doing especially in the winter. As luck would have it Wendel Lambert from Ulysses Kansas had been out to Las Vegas also and had been trained to do the installations for Cascade pressure cowls.  Wendell owns Northstar Aviation, which is where our aircraft’s were scheduled for their annual inspections. We dropped the 402’s off at Northstar on our way to Covington Turbine School as it was right on our flight path anyway.  In Okmulgee we spent the week learning ( and forgetting) more than our Ag pilot brains could endure, kind of like drinking from a fire hose. However, the result of our schooling was an overwhelming confirmation that “cooler” is better for a turbine, and in my case the difference would prove itself to be just what I needed.


The boys at Northstar did a great job on our installations. I did have them go the extra mile and calibrate the ITT and trim stick… check everything that could be giving false highs.  They made some adjustments, added a fuel flow monitor so I could do the trend monitoring more completely, and sent me home.


What can I say but WOW!  It’s not the same plane. Now I never have to worry about the temperatures.  I fix my eyes on the torque gauge and fly.  My airstrip is 5000 feet in length so I have the luxury of a long takeoff roll, but my brother’s is very short so we need all the available power we can get at his airstrip.  Both aircraft work identically – the temps, torque’s everything (although I’m probably the better pilot)!!


Guys, I couldn’t be happier. I saved $125,000.00 and have a beautiful looking and performing airplane. I also had the pleasure of working with a couple of top quality men who take pride in their work. While talking with Doran about the air inlets he said the –34 drivers had reported they were seeing a 4gph fuel savings. I’ll bet it will be an even bigger payback during their hot sections. I highly recommend the Cascade Pressure Cowl to everyone.  Doran treated me with honesty and integrity that is rare in our world today. 


Bernie Koch of KOCH – OPERATIONS INC. in Arriba, CO was kind enough to share this unsolicited letter with us.

From: “West River Aerial (Jake Kraft)”

To: “Doran Rogers”

Sent: Thursday, August 03, 2006

Subject: SPRAYER


Hello Doran,

You know the saying that no news is good news. Well, you got through the season without even a peep from me but I can’t keep quiet any longer. Your pressure cowl on my 500 gal thrush with a PT6-34 is great!! I have a very honest 70 degree drop in the ITT. I can’t over temp even on a 100 degree day and we had a bunch of those this year. What a tool! I will never understand why the two big manufactures we have in this country don’t have this as standard equipment. And why Pratt doesn’t insist it being on for their engines!! They must like selling hot section parts. What a waste of FREE power and there isn’t anything free with these engines. All I can say is I don’t have any regrets having you put this on my aircraft for me and would definitely recommend it to anyone who wanted to get the true potential out of their PT6. The cowl looks great and has held together well, you have some good mechanics in your shop.


Very Impressed and Thanks

Jake Kraft

West River Aerial, Inc.