---------------------------------------------------------- Allegro-List Digest Archive --- Total Messages Posted Mon 05/26/08: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:51 AM - Re: Allegro 2000 CG (aerosiam) 2. 10:07 AM - Vortex generators tested on Allegro (aerosiam) 3. 11:01 AM - Re: Stall Warning System (aerosiam) 4. 11:31 AM - Re: Rotax 912ULS overheating issues (aerosiam) ________________________________ Message 1 _____________________________________ Time: 09:51:01 AM PST US Subject: Allegro-List: Re: Allegro 2000 CG From: "aerosiam" Attached is Thom Riddles weight and balance excel My 2005 Allegro 100hp came with the CG just slightly forward of the forward limit so I fitted a 2.2lb weight in the tail. As you can see from the excel, 2 pilots full fuel and baggage gives 29% Forward limit is an 85lb pilot. Even putting 44lb baggage in the equation (max 22lb), it gets nowhere near the rear CG limit. Empty is 10 inches, 1 inch forward of the forward limit Regards Paul Read this topic online here: http://forums.matronics.com/viewtopic.php?p=184886#184886 Attachments: http://forums.matronics.com//files/wandb_tail_weight_490.xls ________________________________ Message 2 _____________________________________ Time: 10:07:30 AM PST US Subject: Allegro-List: Vortex generators tested on Allegro From: "aerosiam" VORTEX GENERATORS Please open Word attachment. The speed data has not come out correctly on this post. (The flap settings have appeared as a phone number!)Pictures of VGs fitted to Allegro in another post. Allegro 2000 first test flight with Stolspeed VGs. 3 flights, total time about 2.5 hrs flown with instructor Michael Peare Density alt 2,600' CG close to forward limit Weight 490 KG Pictures and info for VGs at www.stolspeed.com Test 1 - VGs half span Test 2 - VGs full span Test 3 VGs full span but leave gap of 80cms (30in) at wing root POWER OFF POWER ON 3000 RPM Flap setting 0 15 48 0 15 48 NO VG 45 40 36 44 38 35 HALF SPAN VG 43 36 36 43 37 34 FULL SPAN VG 41 36 34 38 36 34 Stall sp reduced 4 4 2 6 2 1 Airspeeds in knots Dynon and ASI both calibrated No VGs Aircraft breaks and drops right wing. Significant wing drop with power on. Little buffet just before stall. Ailerons have adverse yaw close to stall. Needs some rudder to correct wing drop. Ailerons a little heavy. Test 1 - VGs half span and VGs on vertical stabiliser Ailerons lighter, more effective. A lot of buffet warning Power off - no break, no wing drop. Stick full back, aircraft nose high and buffets Power on - mild wing drop, quick recovery. Can be rolled 30 left 30 right a few knots below stall. Stable. Ailerons can be used to roll level after stall. Can fly 40 degree banked turn few knots below stall. Aircraft buffets and purpoises but does not break. Small reduction stall speed except power off reduced 4 kts @ half flap Test 2 - VGs full span Ailerons same as test 1. Reduced buffet Power off - mild wing drop, quick recovery. At zero flap, no break, descends 500'/min Power on - break and mild wing drop, quick recovery Significant reduction in clean stall speed, power on/off. Aircraft can be trimmed to fly at 38 knots full flap with very high nose angle. Stable. Test 3 - removed VGs at the wing root (approx span of the elevator) to try to get the strong buffet in test 1 with half span VGs. Made no difference. Notes. Factory stall warning gave good warning under all tests. For example power off, full flap the stall warn sounds @ 42, buffet @ 37 and stall 34 Right wing drop even from left turn with left rudder 34 kts 3,800 RPM Increasing RPM to 4,000 full flap, stall speed same, 34 kts, wing drop not significantly worse with more power (very different to standard config with no VGs) Stall speeds in POH say 43 - 39 - 35 kts Conclusion The VGs on the tail did not seem to give a noticeable difference in handling. Results broadly similar to many aircraft i.e. large difference in clean stall speed, less so in approach configuration. Half VGs gave the best handling but a small reduction in stall Full VGs gave good reduction of stall speed but less buffet and more wing drop than half span The Allegro has powerful 48 degree flaps. The inboard span stalls long before the outboard and the VGs cannot help much. Big difference in aileron response. Much nicer to fly. Although Allegro has 11m wingspan, it feels light in roll. Surprisingly, removing the VGs close to the wing root did not bring back the buffet that was present with half span VGs These VGs were a simple and inexpensive way to improve safety and handling Read this topic online here: http://forums.matronics.com/viewtopic.php?p=184892#184892 Attachments: http://forums.matronics.com//files/vg_allegro_report_vgs_351.doc ________________________________ Message 3 _____________________________________ Time: 11:01:36 AM PST US Subject: Allegro-List: Re: Stall Warning System From: "aerosiam" Hugh My LED was red-green. It stopped working within a few hours. The red would come on with start up then change to green at take off speed. Red indicated a stall. I think I sent you some photos a while back when I had my panel out. I can look for them again. The system is a little quirky and sometimes sounds on the ground when taxying in a cross wind but it works well in the air and gives about 5 to 7 kts warning before the break. Regards Paul Read this topic online here: http://forums.matronics.com/viewtopic.php?p=184901#184901 ________________________________ Message 4 _____________________________________ Time: 11:31:16 AM PST US Subject: Allegro-List: Re: Rotax 912ULS overheating issues From: "aerosiam" We fly an Allegro 2000 100hp in Thailand with temperatures around 28 to 35 degrees (82 to 96F). It would overheat within 10 mins of startup at 2200 rpm and needed very gentle climbouts. We fitted EvansCool and opened a circular hole in the lower cowling and enlarged the oil cooler opening about 3 times. (See picture) The oil runs too cool now and once a day we have to get the oil temperature over 100C (250F) - Rotax say this must be done to avoid condensation problems in the oil system. The additional oil cooling and reduction in cyl head temp with the extra airflow is now acceptable and it never goes over 130C. (Max 150C) We checked the senders in boiling water - they were underreading on the guage by about 10F. The best solution is probably to fit the Rotax cooling baffle. I have a friend with an 80hp who has it fitted and the opening is only about 1.5 in diameter but it never overheats. The problem is that the baffle is very expensive. Regards Paul Read this topic online here: http://forums.matronics.com/viewtopic.php?p=184906#184906 Attachments: http://forums.matronics.com//files/img_0646_151.jpg ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message allegro-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Allegro-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/allegro-list Browse Digests http://www.matronics.com/digest/allegro-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.