Been asked to write some introduction piece also about the K35 Bonanza, which my club now has in its fleet. Here we go.
The K35 Bonanza (1959 model year) belongs to the second generation of Bonanzas. It’s one of the very early models with fuel injection. It has the IO-470-C delevoping 250hp at 2600 RPM. It is NOT mogas-approved. The (hydraulically-adjusted) prop is a Beech two-blade, 278-100. This aircraft model sold for 25,000$ in 1959. 436 K35s have been built.
While not as light as the first gen Bonanzas, it isn’t as heavy as the later 35 Bonanzas from the 60s and 70s. MTOW is 1338kg. Empty weight on this one is a bit high at 938kgs, leaving (only) 400kg of useful load. (I am having some doubts on that weighing report).
Standard tanks are 50 gallons, but most K35s (including this one) also have wing aux tanks, bringing the total to 70 gallons. This one here even also has big Osbourne wing tip tanks, bringing the total to 110 gallons, for almost ten hours of economy cruise! Obviously, it’s almost a one-seater with all that fuel! Also, fuel tank management is weird and complex. More on that in an second.
Looking at the panel, it is still quite vintage in layout (including the nevertheless very nice throw-over yoke) but it has the important stuff (GNS430W and an S-TEC30). It will get a modest panel update shortly, including a Garmin G5.
Notice the famous “piano keys”, also for the flaps (LH side!) and the landing gear (RH side!).
But for sure, the quaintest bit about this aircraft is the fuel system. Here is a look at the “fuel switch panel” (behind the pilot’s left foot). It is imperative that the pilot fully understand this system before taking this aircraft towards the limit of its range.
Also, the aircraft only has two fuel gauges, for four (!) wing tanks, and you have to select (via the piano keys) which tanks‘ fuel quantities you want to show on the gauges.
Another very important bit is that, this being a very early iteration of fuel-injected engines, the fuel pump always delivers a CONSTANT amount of fuel, about 25 GPH, IIRC. So, any fuel not actually used is returned to the fuel tanks,. However, when the AUX tanks are used, then it doesn’t return to the aux tanks, but always to the LH main tank. This leads to a few things:
-when the tanks are full, you always have to take-off on the LEFTHAND main tank, in order to “make room” for fuel returned from the auxes. Otherwise, you will be pumping fuel overboard, at an alarming (and expensive!) rate
-in other words, when flying on the aux tanks, you can watch the LH main tank quantity INCREASE!
-when flying on the aux tanks, even though they are 20 gallons in total, they will only “last” about 45-50 minutes in cruise flight!
It can all easily lead to a lot of confusion and mis-calculations. Easy to imagine how so many pilots have come to grief with all this complexity. I am thinking of IMC, high workload situations, weather, navigation, equipment malfunctions, passengers, etc. leading to trouble with the fuel management…
Anyway, let’s briefly look at cruise performance. At FL55 and a bit above standard temperature, here she is doing 139 KIAS, about 152KTAS, burning 12 GPH (47 litres). She isn’t set up perfectly yet, so let’s call that 155-158 KTAS at the mid altitudes.
Performance-wise, it is thus very similar to the C33 Debonair I also fly.
Just gotta love those wing shots:
And look at those cool red leather seats:
The manual gear extension is via the classic Bonanza handcrank, located behind the RH front seat:
A few more shots of the exterior:
Detail shots of the famous “ruddervators”, which are so much talked about these days on Beechtalk, etc., with the supply of the required magnesium skins having finally dried-up, world-wide.
Finally, if you want to fly this characterful, iconic machine, let me know and book an airline flight to Frankfurt, which is 20 minutes by car from its home base, EDFZ. This club is also open to “non-members”.
Boscomantico great write up, might you add some pilot notes on any special flying techniques or is it very straightforward.
The DA40 TDI is similar : engine takes fuel from the left wing tank, and send its surplus to the right fuel tank. The pilot controls the transfer pump between the right and the left tank. It gets done after some training.
Great report again Bosco. This club makes many pilots jealous ! Maybe a fly-in someday to EDFZ to show the planes ?
Really nice write up on a really nice aeroplane. Yes that fuel system guaranteed to bring some nightmares..All done really by feel due to the positioning of the fuel unit. How many hours on similar before you let the members go out? I assume a full check out also?
@ jujupilote I understood that in the DA40 unused fuel from the left tank is returned to the left tank but the pipework which carries it passes through the right hand tank in order to heat the fuel in the right tank.
Robert: I really haven‘t so much to say about the flying bit. It flies and handles nicely. But doesn‘t get me totally excited either. TBH, I‘m more of an autopilot guy, even in a Bonanza. Landings are very easy and always very smooth. But that‘s just my opinion. The actual flying is easy. It‘s more the quirks of the design, especially the lack of ergonomics in the cockpit which makes it a challenge.
Juju: yes, EDFZ might be another good candidate for some fly-in. Ingelheim, Eltville, Ruedesheim etc. are all very beautiful. I have really started to love this „Rheinhessen“ area (my girlfriend lives right around the corner from the airfield at Mainz, whereas for me, it‘s a 40 minute drive from Frankfurt…).
Beechbaby: we have no fixed rules on minimum hours and checkout requirements. It will depend on the single candidate. But generally, the owner wants to keep it straightforward.
Oh, forgot to say, I knocked up a little video as well:
Great report, video and photos. Strikes me as a bit of an ergonomic nightmare. There is a reason why gear and flap levers look like they do now!
It’s very satisfying mastering an aircraft with quirky ergonomics. Makes you feel like something from Fate is the Hunter.
Having said that, the gear piano key does have a “wheel” on it, so some though was given to avoiding a mistake when doing things by feel.