What engines are recommended for this airplane?
There are a lot of engine options out there. Right now, the best engine options for the plane are the Rotax 912UL/ULS and the D-Motor LF-39 (dependent on US availability). Don't worry! We've gone to great lengths to keep the narrow look of the cowl. You will not be disappointed with how the cowl looks. There are also many other options on the market, such as the Continental O-200 or automotive conversions. The prototype airplane runs a Rotax 912ULS with an after muffler for a slightly deeper sound. The engine is fully-cowled and runs flawlessly.
Why 95% scale and not 100% scale?
What is the point in downsizing to 95% scale? The answer here is quite simple: cost and simplicity. After all, most people can’t drop 150k on a full size replica, much less 250-500k on the real deal.
The Rotax 912UL/ULS line of engines is the current front-runner for engine options. Because these options don’t offer the big power of a Menasco, Tigre, or LOM engine that a full size ST would require, a weight reduction was mandatory. Less weight means less power required which means we now have less expensive engine options. No need to plunk 30k on a Menasco and then worry about parts availability.
The empty weight range of the ST-L is 800-830 lbs, depending on the build and pilot weight. With 125 horsepower, we have a higher power-to-weight ratio and lower wing loading than the ST-A. Shoulder and leg room are increased, as well. Pilots of 6'5" have tried on the ST replica and have confirmed the cockpit is roomier than the original.
So, it is a small difference in size with huge implications on weight, performance, cockpit size, and cost to build/operate/maintain. Even parked next to a full size ST, most people will never notice the size difference. At 100% scale, there would be no possible way to meet our cost, engine, performance, and baggage goals. That 5% is the difference between a $75,000 replica that meets customer criteria and a $150,000 replica that under-performs.
How accurate is this replica?
This replica is a fairly faithful representation of the Ryan ST, ST-A, ST-A Special, PT-16, PT-20, and ST-M. It is all-metal with optional cowlings and fairings of fiberglass or aluminum, depending on the builder's tastes. Certain things had to change to bring the weight down and make manufacturing easier. For instance, the bulkheads were designed with a different flange style. There are various other small differences, but we strived to keep the outward appearance as accurate as possible, along with the overall look and feel of the interior. Some notable changes are: modern airfoil, simplified elevator trim, hydraulic brakes, better tailwheel geometry, modernized landing gear that solves the "squirrely" nature often reported of the original ST, modern lightweight wheels, simplified shocks that are lighter and easier to maintain, simplified wire attachments at the lower landing gear, simplified modernized control systems, and heavy duty aluminum I-beam wing spars. This replica retains the original-style wires with the one strut above the wing stub. All-in-all, it is a modern airplane that is very-well disguised as a classic.
How many hours will it take and how much will it cost to build this plane?
Estimates indicate about 1500 hours for construction and averaging 75k to 90k US for a finished, flying airplane. The biggest cost factor will be the engine used and the ability of the builder to scrounge for inexpensive (but airworthy!) parts. Compare that price to a self-built hot rod, and the numbers are roughly the same, maybe a bit lower for the airplane (cars are expensive). When we first set out to design this plane, our end-goal was to afford people the opportunity to build a replica of one of the most desirable aircraft ever built, but at a reasonable price.
I am a big person. Will I fit the ST replica?
The replica was designed to take a pilot as light as 150 lbs and as heavy as 220 lbs. We have confirmed the cockpit is actually roomier than an original and will fit somebody at least 6'5" tall (and likely much taller). WATCH YOUR WEIGHT AND BALANCE!!! This airplane will not be forgiving of weight and balance negligence. Because the pilot is so far aft of the CG, the less you weigh, the less your plane will weigh (less ballast required). The ideal pilot weight would be around 180 lbs, but again, up to 220 lbs.
I have never built an airplane. Is this too difficult for me?
Don’t ever tell yourself something is too difficult. The key to completing a project like this is to jump in and deal with problems as they arise…ONE AT A TIME. Yes, problems will arise. You are building an airplane, after all! But when those problems creep up, treat them individually. When one task is conquered, you are ready for the next. The included instruction manual also helps to keep things going smoothly, outlining the order of operations and showing you how to deal with manufacturing methods.
Can a PT-22 replica be made from this Ryan ST replica?
This is an easy answer that becomes a complicated one. While the Ryan ST and PT-22 look similar, they were vastly different designs that had vastly different mannerisms. You can make a PT-22 “look-alike”, but not a replica. One plane you CAN replicate was the predecessor to the PT-22, the PT-20A, another radial-powered design that had much more in common with the original ST.
What variants can I replicate from this design?
There were many variants of the Ryan ST that can be replicated using this 95% scale plane as a foundation. The variants are ST, ST-A, ST-A Special, STM, STM-2, PT-16, PT-20, and PT-20A (radial-powered). In addition to those variants, other oddball things have shown up on the original STs, including bubble canopies and a sliding canopy that was supposedly developed for Canadian planes.
What types of rivets are used on this plane?
The airplane was designed with a mix of solid rivets and structural blind rivets. Solid rivets are just as easy to use once you have a small amount of practice. Rivets used depend on the part. There are many areas where only solid rivets are acceptable, so please follow the plans carefully.
Will this airplane hold its resale value?
It is difficult to predict any market. As of writing this, it is our opinion that the airplane will have excellent resale value once completed. After all, the only other option is to go purchase a real Ryan ST at a price of 150-500k.
Unless noted, text, photos, and website are Copyright Timber Tiger Aircraft, Inc. Nick@TimberTigerAircraft.com
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Timber Tiger Aircraft, Inc. Montrose, Colorado
ST-L Sub-Kit: Flying Surface Kit
CAD model by Glenn Gordon
ST-L Sub-Kit: Fuselage and Landing Gear Kit
ST-L Sub-Kit: Finishing Kit
Required to Complete Your ST-L: