Useful accessories

There are a lot of useful accessories around on the market. Some I find more useful then others. Accessories come in many fields : avionics, cabin, wing, engine etc. . Let me show you what I put into my DUKE and what I think of it. Please send me a message to  and tell me what your comments are. Later on I will be discussing some modifications and accessories friends put on their DUKE`S

Panel Accessories :

Somehow a lot of DUKE Pilots find it difficult to reach TBO on their engines. Very often engine overhauls after around 1.000 hours have to be performed. Since they are quite costly they have to be avoided. And they can be avoided. The Lycoming TIO-541 engine is a reliable and beautiful piece of machinery. But is obviously different from a IO-360. One key problem is temperature. The specific airflow in the cowling produces CHT`s that may differ up to 40 deg. C. from one cylinder to another. One really useful accessory to be aware of that and to learn from it`s indications is the GEMINI 1200

GEMINI 1200 with 28 probes. [Gemini 1200]12 X EGT, 12 X CHT, 2 X TIT, 1X OAT and 1X IAT

One big cause for engine malfunction is overtemperatures in the cylinder heads. This may lead to valve sticking and and other serious damages. The build-in CHT temperature gauge gives you an indication of only one cylinder. On the DUKE this probe is connected to no. 5 cylinder. I have flown a lot of DUKE`s; none of which had it`s hottest cylinder as no. 5. The airflow within the cowling tends to go some mysterious ways. Somehow at least in cruise cylinder no. 3 always seems the hottest by far. The GEMINI 1200 is a valuable instrument during all phases of flight. In climb you know exactly when and how for to open the cowl flaps. Same in cruise. On hot summer days I regularly get a reading of over 225 deg, C. over 18.000 ft. on the 3rd cylinder which demands the cowl flaps to be opened for a couple of inches (The build-in probe is far lower as I mentioned). In descent you are aware of how rapidly your heads cool down and better leave your power levers where they had been in cruise.

Limitations : The gemini comes with a HP palmtop computer. On that the GEM software is installed. Please buy a connectivity pack with you new unit. It lets you connect the palm top computer to you PC. The palmtop eats up it`s batteries like nothing. Once they are gone so is the software and you will have difficulties configuring your unit. It would be a big advantage if the manufacturer of the GEMINI 1200 would supply it`s units with a disk on which you find the software.The ability to read out the stored data of the GEMINI 1200 is very useful and helps in diagnosing engine trouble. Another limitation are the probes. With 24 engine probes an the Duke be prepared to replace at least one every year. Those probes are good and accurate. Be aware of one thing : the TIT probe uses a thread opposite to the build in TIT probe which should stay in the panel. The flow of the exhaust gases in that pipe are quite miraculous. The -calibrated- build-in probe shows say 875 deg. C. while the GEMINI 1200 probe shows only 810 deg. C. Why ? I don`t know. Anyway there is nothing wrong with the instruments. It simply is a fact. That is why I recommend to leave the build-in TIT in the panel because if you lean to max TIT on the GEMINI 1200 you overheat your engine. If you swap the build-in instrument for the GEMINI 1200 make sure you put it`s probe where the old probe was.

Rating : a clear and definite MUST in every Duke panel. No other accessory is more worth the money than that one.For about $ 5.000 installed it can save you ten thousands in preliminary overhaul and give you peace of mind over all phases of flight that your two hearts are beating in tune.

No aircraft manufacturer was and is able what every car manufacturer in the world can do easily : to produce accurate means of fuel measurement as standard equipment. Beechcraft is no big exemption from that rule. I own a Duke and a B24R. On both aircraft the fuel quantity indicators are lousy. Look into any other brand and you find the same. Somehow aircraft industry cannot produce long lasting probes in the tank, especially when they have to deal with multiple tanks. On the Duke my fuel indicators are accurate when the tanks are full and when they nearing emptiness. Everything in between is pure guesswork. The Fuel Flow meters on the Duke are somehow more accurate since they do not use row fuel pressure for calculation and indication but little turbines in the flow. Anyway the indication is little arms and feathers and therefore a permanent victim of friction. Accuracy is soso. A normal fuel flow meter on the Duke looks like this :

For leaning and a rough calculation of your fuel flow : Beechcraft`s build-in instrument.

One thing is for sure; the instrument is long lasting and reliant, on many S/N`s it uses an inverter to be powered from

If you want to have more information about how much your engines is consuming and especially how long you can still stay in the air with the given powersetting, you are best off with a fuel computer. There are some brands on the market, let me name two : Hoskins and Shadin. My favorite is Shadin because I like the display better. You can have it in different shapes, with GPS output or without. Mine is without (unfortunately). and looks like this :

Quite simple but powerful : Shadin`s Digiflow with all information you need in a format you will appreciate. It is simple to understand and interpret and you have all the impotent information at one glance. Fuel Flow of both engines and time remaining to total quietness. Do not try it`s accuracy in flight !

The GPS version has one more turning knob on which you can for instance have your remaining fuel at destination displayed.


Last updated 10.11.96