Sherwood Ranger Ballistic 472.5kgs (German approval)


Here you will find the latest news and information on the Sherwood Ranger Ballistic developed for the German market with a MTOW of 472.5kgs and incorporating a Ballistic Recovery System.


May 2013



Well the finished Sherwood Ranger DS on display at Aero Expo Friedrichshafen, still some test flying to do and some final niggles to be sorted but she flew on her first flight straight out of the box, no adjustments, no rigging changes, nothing.




April 2013


It has long been known that when you have completed 95% of your aircraft build there is just 95% left to do....well whoever said it was 95% right.


With Friedrichshafen rapidly approaching the build on D-MSLZ has accelerated, the piles of paperwork have grown disproportionately (an aircraft doesn't fly until its MTOW is equaled by the weight of the associated paperwork) and the stress levels have resulted in many sleepless nights.


Below are a few pictures of the build as it reaching completion. D-MSLZ has a control panel like a 747 incorporating such features as synthetic vision GPS, TCAS, 8.33 radio and Mode S transponder just for starters. Under the cowlings is a ULPower 260i twin pumper fuel injected engine with full FADEC control, now we have it running it looks to be a good but very heavy unit. We spent 3 days working on the engine that refused to start out of the box, to cut a really long story short 3 of the fuel injectors had frozen with contamination, we believe from pre-shipment testing with unknown Unleaded fuel, nothing else explains the issue but the loss of 52 man hours and shipping components around Europe for fun took the edge off the installation.


The UL260i is a heavy lump, our Rotax 582 powered unit weighs in at 215kgs with basic flight instruments D-MSLZ weighs in at 277kgs or 265 kg's excluding the BRS system................50kgs gain, this engine could be made lighter and be really interesting to more builders I am sure.


Anyway enjoy the pictures



Port and Starboard shots of the final UL260i engine installation, baffles and seals in place oil cooler hooked up and ready for action. We kept the installation a show presentation, we would be proud to take the cowlings off at any exhibition so builders can see the quality of installation.



Just a small part of the overall wiring system, it is a tight install and the drawings for the system cover 3 A1 print outs. This is just the reverse side of the pilots panel, the firewall region and P2 panel are equally interesting, complex yes, work of art yes, results impressive.




This is D-MSLZ on our aircraft lift, it takes completed aircraft from our upper assembly area down to our final fitting workshop, as will all our in house builds we cover in ORATEX UL600 the outstanding weight saving light aircraft covering system.



D-MSLZ straight and level having the lower wings fitted, with the basic fuselage in the level condition it took us 30 minutes to get both lower and upper wings on and the interplane struts fitted, took another hour to get the landing and flying wires fitted but not tensioned, that was the easy bit, it is all the final fittings aileron hook ups and a like that takes the time.



Getting close D-MSLZ along side our demonstrator G-TLAC, the remaining work at this time is wing root fairing's to be fitted, interplane strut infill panels to be fitted, final strobe hook up, registrations to be fitted, pitot system final fitting, fuel and test flight..............................................


I will post both photographs and video of the taxi trials and test flight.


January 2013


Progress to the German aircraft Call sign D-MSLZ has made significant progress and as the old saying goes 90% done just 90% left to go...............................


The pictures below show the aircraft fully rigged with landing and flying wires and ailerons wired up as well, all working exactly as it should, in actual fact when it was rigged Mac and I did a rigging measurement check from a common point on the wing tip to the stern post reference point, 1mm difference, that is accuracy, when you consider that a Socata TB10 for the same measurement has a tolerance of plus or minus 32mm??


The lower photographs show the UL260i engine cowlings that have had to be designed, a buck made and a new tool made, not an insignificant task to say the least but the first off's have been delivered and they fit well and look sweet.






July 2012


We are continuing to make advances with our German approval program. The newly appointed stress engineer Thomas Schaich is proving to be a pleasure to work with and unlike his predecessor is being very helpful on clarifying issues and giving guidance in terms of the schemes that we need to work to to show compliance to the DAeC. Mike Robins, our stress engineer is working hard in the background keeping us busy generating the test schemes and overseeing the results in the first instant. A couple of videos below show the lengths that we are going to to get the Sherwood Ranger into the German market, Lanitz Aviation has multiple orders on the table for our aircraft.


Sherwood Ranger Elevator Ultimate Load Test



Sherwood Ranger Rudder Ultimate Load Test



We can now confirm we have completed the following load testing to a MTOW of 472.5kg:-






Tailplane and fin in asymmetric and rear fuselage

Fuel tank


We will shortly be testing:-


Landing gear

Control system

Engine mount



and last but not least the ballistic recovery system including the central fuselage section.


We continue to work to gain approval from the DAeC, a complete stress analysis has taken place by our stress engineer to conform to LTF-UL, this has taken the best part of 6 months and accrued significant costs. We are now manufacturing sacrificial airframes to undertake both load testing and ballistic recovery parachute testing to the increased weight load of 472.5kgs, all of this has been hindered by Junkers the manufacturer of the BRS system issuing confirmed but apparently incorrect figures for test loading. The LAA (Light Aircraft Association) is currently reviewing the complete report prior to issuing to the DAC and will be advising us of any subsequent testing needed. As soon as we have some meaningful pictures they will be posted.


May 2012


As of May 2012 we have had a new German stress engineer assigned to the project, Thomas Schaich. We have forwarded our stress analysis reports to him, these where made in accordance with LTF-UL and as a result he has asked for some changes to be made and new calculations made, this has been done and at this stage we believe they are acceptable. We are awaiting the final stress analysis of our engine mount design for the UL260i engine, the engine as specified by Lanitz Aviation our sole Distributor for the German market place, once this analysis has been completed this to will be submitted to Thomas.


It is our understanding that once we have the written reports in place we can then undertake the physical testing of the airframe to Ultimate load conditions, this will basically destroy a complete airframe,. We also have to undertake a worst case Ballistic Recovery System load test , we have built a one off airframe for this test as the loads imposed on it will exceed 2.6 tonnes in various directions from the Ballistic Recovery System mounting points.


Progress is being made it has been slow to this point due to the previous engineering company assigned to the project, we have high confidence that with Thomas this process will now push forwards, please bookmark this page and check back every 2 or 3 weeks for updates and pictures.




To be documented




The end of June and beginning of July saw the testing of the Empennage, the rear fuselage, fin, tailplane, rudder and elevator, the testing seemed incredibly brutal in terms of the loads applied yet the Sherwood Ranger once again showed its incredible strength and resilience and successfully passed each stage through Limit load and Ultimate load. Shown below is probably one of the more severe tests an asymmetric load on tailplane and fin, tailplane load can be clearly seen with the weights hanging vertically whilst the asymmetric fin loads are reacted through the pulley system those weights are the once hanging from the structural beam to the left of the photograph.





August saw significant testing of the control system, this meant exerting forces on both control columns and rudder pedals through to the operational bellcrank controlling those surfaces. In terms of the test protocol and for example we had to exert a force on the front control column forwards whilst exerting a rearward force on the rear column, pull the front stick to the right and rear to the left (see photograph below). All of these tests were once again to 1/2 limit load, Limit load and then on to Ultimate load, as with other tests so far no catastrophic failure has occurred and all components tested so far could be used safely used again i.e. no permanent deformation has occurred.





We are delighted to confirm that we have completed the wing loading test to Ultimate load for the 472.5kg Sherwood Ranger, this involved mounting an upper and lower wing panel in the inverted position, with an incident angle of 5 and 1/4 degrees to a structure that would not deflect under the loads we were going to apply, in this case the structure of our building.


After making a pair of wings, interplane strut and landing and flying wires then came the task of making a suitable fixture to hold the wings in an inverted flying attitude at the prescribed angle of incidence and mounting the whole assembly to the building structure in such a way that deflection could be measured accurately and consistently. We also had to arrange a system that would allow both wings to be supported during the loading phases and then smoothly released to take the full loads when applied.


The loading sequence was with the wing supported to load to 1/2 Limit load then release the supports and measure the deflection at both the wing tips and the aileron roots, remove the load and measure deflection once again. This process was repeated at Limit load and them Ultimate load which is 1.5 times Limit load, in layman's terms we had the weight of a Honda Accord car balanced on those 2 wings.



During all stages of the test there were NO cracks, creaks, bangs or other noise, after ultimate load we noticed that the thimbles on the flying wire had flattened out by about 2.2mm which resulted in a slight wing drop against datum's. I estimate that we could have increased the loads on the wings under test to 2 times limit load before we reached failure, as we have kept the wings we might do this when time permits.




Wing Ultimate Load Test for LTF-UL with MTOW of 472.5kgs





U/C Drop Test loaded in excess of MTOW and with Max forward C of G





Ballistic recovery parachute testing on 12.12.12